Mitigating Log4Shell and Other Log4j-Related Vulnerabilities


The Cybersecurity and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), National Security Agency (NSA), Australian Cyber Security Centre (ACSC), Canadian Centre for Cyber Security (CCCS), the Computer Emergency Response Team New Zealand (CERT NZ), the New Zealand National Cyber Security Centre (NZ NCSC), and the United Kingdom’s National Cyber Security Centre (NCSC-UK) are releasing this joint Cybersecurity Advisory (CSA) to provide mitigation guidance on addressing vulnerabilities in  Apache’s Log4j software library: CVE-2021-44228 (known as “Log4Shell”), CVE-2021-45046, and CVE-2021-45105. Sophisticated cyber threat actors are actively scanning networks to potentially exploit Log4Shell, CVE-2021-45046, and CVE-2021-45105 in vulnerable systems. According to public reporting, Log4Shell and CVE-2021-45046 are being actively exploited.

CISA, in collaboration with industry members of CISA’s Joint Cyber Defense Collaborative (JCDC), previously published guidance on Log4Shell for vendors and affected organizations in which CISA recommended that affected organizations immediately apply appropriate patches (or apply workarounds if unable to upgrade), conduct a security review, and report compromises to CISA or the FBI. CISA also issued an Emergency Directive directing U.S. federal civilian executive branch (FCEB) agencies to immediately mitigate Log4j vulnerabilities in solution stacks that accept data from the internet. This joint CSA expands on the previously published guidance by detailing steps that vendors and organizations with IT and/or cloud assets should take to reduce the risk posed by these vulnerabilities.

These steps include:

  • Identifying assets affected by Log4Shell and other Log4j-related vulnerabilities, 
  • Upgrading Log4j assets and affected products to the latest version as soon as patches are available and remaining alert to vendor software updates, and
  • Initiating hunt and incident response procedures to detect possible Log4Shell exploitation. 

This CSA also provides guidance for affected organizations with operational technology (OT)/industrial control systems (ICS) assets.

Log4j is a Java-based logging library used in a variety of consumer and enterprise services, websites, applications, and OT products. These vulnerabilities, especially Log4Shell, are severe—Apache has rated Log4Shell and CVE-2021-45046 as critical and CVE-2021-45105 as high on the Common Vulnerability Scoring System (CVSS). These vulnerabilities are likely to be exploited over an extended period. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK strongly urge all organizations to apply the recommendations in the Mitigations section. 

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK encourage leaders of organizations to review NCSC-UK’s blog post, Log4j vulnerability: what should boards be asking?, for information on Log4Shell’s possible impact on their organization as well as response recommendations.

Note: this is an evolving situation, and new vulnerabilities are being discovered. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK will update this CSA as we learn more about this exploitation and have further guidance to impart.

Click here for a PDF version of this report.

Disclaimer

The information in this report is being provided “as is” for informational purposes only. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK do 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, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, or NCSC-UK.

Log4Shell

Log4Shell, disclosed on December 10, 2021, is a remote code execution (RCE) vulnerability affecting Apache’s Log4j library, versions 2.0-beta9 to 2.14.1. The vulnerability exists in the action the Java Naming and Directory Interface (JNDI) takes to resolve variables. Affected versions of Log4j contain JNDI features—such as message lookup substitution—that do not protect against adversary-controlled Lightweight Directory Access Protocol (LDAP), Domain Name System (DNS), and other JNDI-related endpoints. 

An adversary can exploit Log4Shell by submitting a specially crafted request to a vulnerable system that causes that system to execute arbitrary code. The request allows the adversary to take full control over the system. The adversary can then steal information, launch ransomware, or conduct other malicious activity.

CVE-2021-45046

CVE-2021-45046, disclosed on December 13, 2021, enables a remote attacker to cause RCE, a denial-of-service (DoS) condition, or other effects in certain non-default configurations. This vulnerability affects all versions of Log4j from 2.0-beta9 through 2.12.1 and 2.13.0 through 2.15.0. In response, Apache released Log4j version 2.16.0 (Java 8).

CVE-2021- 45105

CVE-2021-45105, disclosed on December 16, 2021, enables a remote attacker to cause a DoS condition or other effects in certain non-default configurations. According to Apache, when the logging configuration uses a non-default Pattern Layout with a Context Lookup (for example, $${ctx:loginId}), attackers with control over Thread Context Map (MDC) input data can craft malicious input data that contains a recursive lookup, resulting in a StackOverflowError that will terminate the process. In response, Apache released Log4j version 2.17.0 (Java 8).

Impact

Log4Shell and CVE-2021-45046—rated as critical vulnerabilities by Apache—are severe because Java is used extensively across IT and OT platforms, they are easy to exploit, and applying mitigations is resource intensive. Log4Shell is especially critical because it allows malicious actors to remotely run code on vulnerable networks and take full control of systems. 

According to public reporting, exploitation of Log4Shell began on or around December 1, 2021, and a proof-of-concept exploit is publicly available for this vulnerability. The FBI has observed attempted exploitation and widespread scanning of the Log4j vulnerability to gain access to networks to deploy cryptomining and botnet malware. The FBI assesses this vulnerability may be exploited by sophisticated cyber threat actors and incorporated into existing cyber criminal schemes that are looking to adopt increasingly sophisticated obfuscation techniques. According to public reporting, CVE-2021-45046 is being actively exploited as well. 

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK assess that exploitation of these vulnerabilities, especially Log4Shell, is likely to increase and continue over an extended period. Given the severity of the vulnerabilities and likely increased exploitation, CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK strongly urge all organizations to apply the recommendations in the Mitigations section to identify, mitigate, and update affected assets.

For more information on these vulnerabilities, see the Apache Log4j Security Vulnerabilities webpage. 

Vendors

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK encourage vendors to:

  1. Immediately identify, mitigate, and update affected products that use Log4j to the latest patched version.
    1. For environments using Java 8 or later, upgrade to Log4j version 2.17.0 (released December 17, 2021) or newer.
    2. For environments using Java 7, upgrade to Log4j version 2.12.3 (released December 21, 2021). Note: Java 7 is currently end of life and organizations should upgrade to Java 8.
  2. Inform your end users of products that contain these vulnerabilities and strongly urge them to prioritize software updates. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK strongly recommend vendors take steps to ensure messaging on software updates reaches the widest possible audience (for example, avoid placing relevant information behind paywalls). Note: CISA is actively maintaining a GitHub page and repository with patch information for products known to be affected by Log4Shell. CISA has also notified ICS vendors that may be affected and has asked them to confirm any assets affected by Log4Shell and to apply available mitigations. 

Affected Organizations with IT and Cloud Assets

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend that affected organizations take the following steps to patch these vulnerabilities in their IT and cloud assets and initiate threat hunting to detect possible compromise. Organizations with OT/ICS environments should review the Organizations with OT/ICS Assets section for additional guidance. Note: this guidance includes resources that may or may not be possible for all organizations. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend that organizations apply the mitigations listed in this advisory to the extent allowed by their environments.
 

1. Identify vulnerable assets in your environment.

Knowing where Log4j and other affected products exist in your environment is key for protecting your networks.

  1. Inventory all assets that make use of the Log4j Java library. According to public reporting, adversaries are patching and mitigating assets they compromise to retain control of assets. To avoid missing such defense evasion, organizations should carefully track assets under investigation.
    1. Assume all versions of Java and Log4j are vulnerable and include them in the inventory.
    2. Ensure the inventory includes all assets, including cloud assets, regardless of function, operating system, or make. Ensure the inventory includes the following information about each asset
      1. Software versions
      2. Timestamps of when last updated and by whom
      3. User accounts on the asset with their privilege level
      4. Location of asset in your enterprise topology
  2. Identify the inventoried assets that are likely vulnerable.
    1. Use CISA’s GitHub repository and CERT/CC’s CVE-2021-44228_scanner to identify assets vulnerable to Log4Shell.

Additional resources for detecting vulnerable instances of Log4j are identified below. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK will update the sources for detection rules as we obtain them. Note: due to the urgency to share this information, CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK have not yet validated this content.

  • To identify server applications that may be affected by Log4Shell and CVE-2021-45046, see TrendMicro: Log4J Vulnerability Tester.
  • For a list of hashes to help determine if a Java application is running a vulnerable version of Log4j, see:
  • For PowerShell to detect vulnerable instances, see:
  • For guidance on using Canary Token to test for callback, see Thinkst Canary’s Twitter thread on using Canary Tokens.
  • For guidance on using Burpsuite Pro to scan, see:
  • For guidance on using NetMap’s Nmap Scripting Engine (NSE), see Divertor’s GitHub page: nse-log4shell.
  • See Florian Roth’s GitHub page, Fenrir 0.9.0 – Log4Shell Release, for guidance on using Roth’s Fenrir tool to detect vulnerable instances.

2. Mitigate known and suspected vulnerable assets in your environment.

   A. Treat known and suspected vulnerable assets as compromised. These assets should be isolated until they are mitigated and verified (step 2.D). The method of isolation that you should use depends on the criticality of the asset. Possible isolation methods include:

  • Physically removing the asset from the network (e.g., unplug the network cable);
  • Moving the asset to a “jail VLAN” with heightened monitoring and security;
  • Blocking at the network layer (a switch or some other device);
  • Implementing a firewall (including web application firewall) with strict port control and logging; or
  • Restricting the asset’s communication, especially to the internet and the rest of the enterprise network.

   B. Patch Log4j and other affected products to the latest version. 

  • See the Apache Log4j Security Vulnerabilities webpage (as of December 22, 2021, the latest Log4j version is 2.17.0 for Java 8 and 2.12.3 for Java 7). Note: patching or updating Java is not enough, you must upgrade the Log4j library itself.
  • For other affected products, see CISA’s GitHub page.

Note: if your organization is unable to immediately identify and patch vulnerable instances of Log4j, apply appropriate workarounds. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend using vendor-provided mitigations when available. Due to the rapidly evolving situation, these workarounds should not be considered permanent fixes and organizations should apply the appropriate patch as soon as it is made available. Additional mitigations are identified below; however, organizations should use these mitigations at their own risk as they may be incomplete, temporary, or cause harmful effects, such as application instability, a DoS condition, or log evasion.

  • Remove the Jndilookup.class from the class path. [1]
  • Delete or rename Jndilookup.class. Note: removal of the JndiManager will cause the JndiContextSelector and JMSAppender to no longer function). [2]
  • Apply a hot patch. 

   C. Keep an inventory of known and suspected vulnerable assets and what is done with them  throughout  this process. It is important to track patching because malicious cyber actors may compromise an asset and then patch it to protect their operations. Organizations should keep a meticulous record of vulnerable assets they have patched to identify whether a threat actor may have patched an asset.

   D. Verify the mitigation has worked, if possible.

  1. Scan the patched/mitigated asset with the tools and methods listed in step 1.B. Use more than one method to verify the mitigation was successfully applied.
  2. Monitor the asset closely.
  3. Remain alert to changes from vendors for the software on the asset. Additionally, see CISA’s GitHub page for known affected products and patch information. CISA will continually update the repository as vendors release patches.

3. Initiate hunt and incident response procedures. Given the widespread exploitation of this vulnerability, CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK encourage all organizations to assume their assets that use Log4j may have been compromised and initiate hunt procedures.

   A. Hunt for signs of exploitation and compromise.

  1. Treat assets that use Log4j as suspect and conduct vigorous forensic investigation of those assets.
  2. Inspect and monitor accounts across your enterprise that exist on or connect to assets that use Log4j.
  3. Inspect changes to configurations made since December 1, 2021, and verify they were intended, especially on assets that use Log4j.
  4. Use CISA’s GitHub page to detect possible exploitation or compromise. 

Additional resources to detect possible exploitation or compromise are identified below. Note: due to the urgency to share this information, CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK have not yet validated this content.

   B. If compromise is detected, organizations should:

  1. Initiate incident response procedures. See the joint advisory from ACSC, CCCS, NZ NCSC, CERT NZ, NCSC-UK, and CISA on Technical Approaches to Uncovering and Remediating Malicious Activity for guidance on hunting or investigating a network, and for common mistakes in incident handling. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK encourage organizations to see CISA’s Federal Government Cybersecurity Incident and Vulnerability Response Playbooks. Although tailored to U.S. FCEB agencies, these playbooks provide operational procedures for planning and conducting cybersecurity incident and vulnerability response activities and detail each step for both incident and vulnerability response.
  2. Consider reporting compromises immediately to applicable cybersecurity authorities. Organizations are encouraged to be as thorough as possible by including information such as IP addresses/domains used to exploit your infrastructure, exploited applications/servers, administrators contact information, and the start and end dates of the attack.
  • U.S. organizations should report compromises to CISA and the FBI
  • Australian organizations can visit cyber.gov.au or call 1300 292 371 (1300 CYBER 1) to report cybersecurity incidents. 
  • Canadian organizations can report incidents by emailing CCCS at [email protected].
  • New Zealand organizations can visit NCSC.govt.nz to report incidents.
  • UK organizations can report a significant cyber security incident at ncsc.gov.uk/report-an-incident (monitored 24 hrs) or, for urgent assistance, call 03000 200 973.

4. Evaluate and apply other mitigations.

   A. Remain alert to changes from vendors for the software on the asset, and immediately apply updates to assets when notified by a vendor that their product has a patch for this vulnerability. Additionally, see CISA’s GitHub repository for known affected products and patch information. CISA will continually update the repository as vendors release patches.

   B. Continue to monitor Log4J assets closely. Continually use signatures and indicators of compromise that may indicate exploitation.

  1. See the exploitation and detection resources listed in step 3.A.(4).
  2. Be aware that there are many ways to obfuscate the exploit string. Do not depend on one detection method to work all the time.

   C. Continue to monitor the Apache Log4j Security Vulnerabilities webpage for new updates. Note: as this is an evolving situation and new vulnerabilities in Log4J are being discovered, organizations should ensure their Apache Log4j is up to date. Identify the software your enterprise uses and stay on top of updates as these may be superseded by other updates and fixes.

   D.  Block specific outbound Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) network traffic.

  1. Outbound LDAP: for most networks, LDAP is used internally, but it is rare for LDAP requests to be routed outside a network. Organizations should block outbound LDAP or use an allowlist for outbound LDAP to known good destinations. Note: this may be difficult to detect on certain ports without a firewall that does application layer filtering. 
  2. Remote Method Invocation (RMI): for most networks, RMI is either unused or used for internal sources. Organizations should block outbound RMI or use an allowlist for outbound RMI to known good destinations.
  3. Outbound DNS: organizations using enterprise DNS resolution can block outbound DNS from sources other than identified DNS resolvers. At a minimum, blocking direct outbound DNS from web application servers configured to use enterprise DNS resolution will mitigate the risks to those systems.

Note: blocking attacker internet IP addresses during this event is difficult due to the high volume of scanning from non-malicious researchers and vendors. The false positives on IP addresses are high. Organizations should focus on looking for signs of successful exploitation and not scans.

Affected Organizations with OT/ICS Assets

Due to the pervasiveness of the Apache Log4j software library—and the integration of the library in operational products—CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK strongly recommend that OT asset owners and operators review their operational architecture and enumerate the vulnerability status against current product alerts and advisories. If a product does not have a security advisory specifically addressing the status of the vulnerability, treat it with additional protections. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK urge patching or deployment of mitigations to reduce the risk of the threat of these vulnerabilities. 

Note: CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend prioritizing patching IT devices, especially those with internet connectivity. Affected internet-facing devices as well as laptops, desktops, and tablets are especially susceptible to exploitation of these vulnerabilities. OT/ICS devices—if segmented appropriately from the IT environment—do not face the internet and, as such, have a smaller attack surface to this vulnerability. Exploitation of IT devices may affect OT/ICS devices if there is insufficient network segmentation that prevents lateral movement. 

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend that OT/ICS asset owner/operators take the following guidance into consideration:

  1. Review operational architecture and enumerate the vulnerability against current product alerts and advisories. If products do not have a security advisory specifically addressing their status of the vulnerability, it is recommended to treat these devices with additional protections.  
  2. Implement the steps listed in the previous section to identify and isolate vulnerable assets in the OT/ICS environment. Understand what type of products in the OT environment would be affected. Many OT/ICS-specific products incorporate vulnerable versions of the Log4j library.
  3. Use a risk-informed decision-making process to apply the latest version of hotfixes or patches to affected devices as soon as is operationally feasible. If patches cannot be applied, mitigations provided by the product’s manufacturer or reseller should be deployed. Note: CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK recommend, as quality assurance, that users test the update in a test development environment that reflects their production environment prior to installation. 
  4. Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the internet.
  5. Locate control system networks and remote devices behind firewalls and isolate them from the business network.

When remote access is required, use secure methods such as virtual private networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that a VPN is only as secure as its connected devices. 

CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK also remind organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and consider reporting compromises immediately.

  • U.S. organizations should report compromises to CISA and the FBI
  • Australian organizations can visit cyber.gov.au or call 1300 292 371 (1300 CYBER 1) to report cybersecurity incidents. 
  • Canadian organizations can report incidents by emailing CCCS at [email protected].
  • New Zealand organizations can visit NCSC.govt.nz to report incidents. 
  • UK organizations can report a significant cyber security incident at ncsc.gov.uk/report-an-incident (monitored 24 hrs) or, for urgent assistance, call 03000 200 973. 

Resources

For more information, resources, and general guidance, including resources and mitigation guidance from industry members of JCDC, see CISA’s webpage Apache Log4j Vulnerability Guidance. Note: due to the prominent and ever evolving nature of this vulnerability, there are multiple unverified published guidance documents that are geared towards Log4j vulnerabilities. CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, and NCSC-UK encourage all organizations to verify information with trusted sources, such CISA, the FBI, NSA, ACSC, CCCS, CERT NZ, NZ NCSC, NCSC-UK vendors.

Source…

APT Actors Exploiting CVE-2021-44077 in Zoho ManageEngine ServiceDesk Plus


Summary

This joint Cybersecurity Advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, Version 9. See the ATT&CK for Enterprise framework for referenced threat actor techniques and for mitigations.

This joint advisory is the result of analytic efforts between the Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) to highlight the cyber threat associated with active exploitation of a newly identified vulnerability (CVE-2021-44077) in Zoho ManageEngine ServiceDesk Plus—IT help desk software with asset management.

CVE-2021-44077, which Zoho rated critical, is an unauthenticated remote code execution (RCE) vulnerability affecting all ServiceDesk Plus versions up to, and including, version 11305. This vulnerability was addressed by the update released by Zoho on September 16, 2021 for ServiceDesk Plus versions 11306 and above. The FBI and CISA assess that advanced persistent threat (APT) cyber actors are among those exploiting the vulnerability. Successful exploitation of the vulnerability allows an attacker to upload executable files and place webshells, which enable the adversary to conduct post-exploitation activities, such as compromising administrator credentials, conducting lateral movement, and exfiltrating registry hives and Active Directory files. 

The Zoho update that patched this vulnerability was released on September 16, 2021, along with a security advisory. Additionally, an email advisory was sent to all ServiceDesk Plus customers with additional information. Zoho released a subsequent security advisory on November 22, 2021, and advised customers to patch immediately.

The FBI and CISA are aware of reports of malicious cyber actors likely using exploits against CVE-2021-44077 to gain access [T1190] to ManageEngine ServiceDesk Plus, as early as late October 2021. The actors have been observed using various tactics, techniques and procedures (TTPs), including:

  • Writing webshells [T1505.003] to disk for initial persistence
  • Obfuscating and Deobfuscating/Decoding Files or Information [T1027 and T1140]
  • Conducting further operations to dump user credentials [T1003]
  • Living off the land by only using signed Windows binaries for follow-on actions [T1218]
  • Adding/deleting user accounts as needed [T1136]
  • Stealing copies of the Active Directory database (NTDS.dit) [T1003.003] or registry hives
  • Using Windows Management Instrumentation (WMI) for remote execution [T1047]
  • Deleting files to remove indicators from the host [T1070.004]
  • Discovering domain accounts with the net Windows command [T1087.002]
  • Using Windows utilities to collect and archive files for exfiltration [T1560.001]
  • Using custom symmetric encryption for command and control (C2) [T1573.001]

The FBI and CISA are proactively investigating this malicious cyber activity:

  • The FBI leverages specially trained cyber squads in each of its 56 field offices and CyWatch, the FBI’s 24/7 operations center and watch floor, which provides around-the-clock support to track incidents and communicate with field offices across the country and partner agencies. 
  • CISA offers a range of no-cost cyber hygiene services to help organizations assess, identify, and reduce their exposure to threats. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate attack vectors. 

Sharing technical and/or qualitative information with the FBI and CISA helps empower and amplify our capabilities as federal partners to collect and share intelligence and engage with victims, while working to unmask and hold accountable those conducting malicious cyber activities.

A STIX file will be provided when available.

For a downloadable pdf of this CSA, click here

Technical Details

Compromise of the affected systems involves exploitation of CVE-2021-44077 in ServiceDesk Plus, allowing the attacker to:

  1. Achieve an unrestricted file upload through a POST request to the ServiceDesk REST API URL and upload an executable file, C:ManageEngineServicedeskbinmsiexec.exe, with a SHA256 hash of ecd8c9967b0127a12d6db61964a82970ee5d38f82618d5db4d8eddbb3b5726b7. This executable file serves as a dropper and contains an embedded, encoded Godzilla JAR file.
  2. Gain execution for the dropper through a second POST request to a different REST API URL, which will then decode the embedded Godzilla JAR file and drop it to the filepath C:ManageEngineServiceDesklibtomcattomcat-postgres.jar with a SHA256 hash of 67ee552d7c1d46885b91628c603f24b66a9755858e098748f7e7862a71baa015.

Confirming a successful compromise of ManageEngine ServiceDesk Plus may be difficult—the attackers are known to run clean-up scripts designed to remove traces of the initial point of compromise and hide any relationship between exploitation of the vulnerability and the webshell.

Targeted Industries 

APT cyber actors have targeted Critical Infrastructure Sector industries, including the healthcare, financial services, electronics and IT consulting industries.

Indicators of Compromise 

Hashes

Webshell:

67ee552d7c1d46885b91628c603f24b66a9755858e098748f7e7862a71baa015
068D1B3813489E41116867729504C40019FF2B1FE32AAB4716D429780E666324
759bd8bd7a71a903a26ac8d5914e5b0093b96de61bf5085592be6cc96880e088
262cf67af22d37b5af2dc71d07a00ef02dc74f71380c72875ae1b29a3a5aa23d
a44a5e8e65266611d5845d88b43c9e4a9d84fe074fd18f48b50fb837fa6e429d
ce310ab611895db1767877bd1f635ee3c4350d6e17ea28f8d100313f62b87382
75574959bbdad4b4ac7b16906cd8f1fd855d2a7df8e63905ab18540e2d6f1600
5475aec3b9837b514367c89d8362a9d524bfa02e75b85b401025588839a40bcb

Dropper:

ecd8c9967b0127a12d6db61964a82970ee5d38f82618d5db4d8eddbb3b5726b7

Implant:

009d23d85c1933715c3edcccb46438690a66eebbcccb690a7b27c9483ad9d0ac 
083bdabbb87f01477f9cf61e78d19123b8099d04c93ef7ad4beb19f4a228589a
342e85a97212bb833803e06621170c67f6620f08cc220cf2d8d44dff7f4b1fa3

NGLite Backdoor:

805b92787ca7833eef5e61e2df1310e4b6544955e812e60b5f834f904623fd9f
3da8d1bfb8192f43cf5d9247035aa4445381d2d26bed981662e3db34824c71fd
5b8c307c424e777972c0fa1322844d4d04e9eb200fe9532644888c4b6386d755
3f868ac52916ebb6f6186ac20b20903f63bc8e9c460e2418f2b032a207d8f21d
342a6d21984559accbc54077db2abf61fd9c3939a4b09705f736231cbc7836ae
7e4038e18b5104683d2a33650d8c02a6a89badf30ca9174576bf0aff08c03e72

KDC Sponge:

3c90df0e02cc9b1cf1a86f9d7e6f777366c5748bd3cf4070b49460b48b4d4090
b4162f039172dcb85ca4b85c99dd77beb70743ffd2e6f9e0ba78531945577665
e391c2d3e8e4860e061f69b894cf2b1ba578a3e91de610410e7e9fa87c07304c

Malicious IIS Module:

bec067a0601a978229d291c82c35a41cd48c6fca1a3c650056521b01d15a72da

Renamed WinRAR:

d0c3d7003b7f5b4a3bd74a41709cfecfabea1f94b47e1162142de76aa7a063c7

Renamed csvde:

7d2780cd9acc516b6817e9a51b8e2889f2dec455295ac6e6d65a6191abadebff

Network Indicators

POST requests sent to the following URLs:

/RestAPI/ImportTechnicians?step=1

Domains:

seed.nkn[.]org

Note: the domain seed.nkn[.]org is a New Kind of Network (NKN) domain that provides legitimate peer to peer networking services utilizing blockchain technology for decentralization. It is possible to have false positive hits in a corporate network environment and it should be considered suspicious to see any software-initiated contacts to this domain or any subdomain.

Log File Analysis

  • Check serverOut*.txt log files under C:ManageEngineServiceDesklogs for suspicious log entries matching the following format:
    • [<time>]|[<date>]|[com.adventnet.servicedesk.setup.action.ImportTechniciansAction]|[INFO]|[62]: fileName is : msiexec.exe]

Filepaths

C:ManageEngineServiceDeskbinmsiexec.exe
C:ManageEngineServiceDesklibtomcattomcat-postgres.jar
C:WindowsTempScriptModule.dll
C:ManageEngineServiceDeskbinScriptModule.dll
C:Windowssystem32ME_ADAudit.exe
c:Users[username]AppDataRoamingADManagerME_ADManager.exe
%ALLUSERPROFILE%MicrosoftWindowsCachessystem.dat
C:ProgramDataMicrosoftCryptoRSAkey.dat
c:windowstempccc.exe

Tactics, Techniques, and Procedures

  • Using WMI for lateral movement and remote code execution (in particular, wmic.exe)
  • Using plaintext credentials for lateral movement
  • Using pg_dump.exe to dump ManageEngine databases
  • Dumping NTDS.dit and SECURITY/SYSTEM/NTUSER registry hives
  • Active credential harvesting through LSASS (KDC Sponge)
  • Exfiltrating through webshells
  • Conducting exploitation activity often through other compromised U.S. infrastructure
  • Dropping multiple webshells and/or implants to maintain persistence
  • Using renamed versions of WinRAR, csvde, and other legitimate third-party tools for reconnaissance and exfiltration

Yara Rules

rule ReportGenerate_jsp {
   strings:
      $s1 = “decrypt(fpath)”
      $s2 = “decrypt(fcontext)”
      $s3 = “decrypt(commandEnc)”
      $s4 = “upload failed!”
      $s5 = “sevck”
      $s6 = “newid”
   condition:
      filesize < 15KB and 4 of them
}

 

rule EncryptJSP {
   strings:
      $s1 = “AEScrypt”
      $s2 = “AES/CBC/PKCS5Padding”
      $s3 = “SecretKeySpec”
      $s4 = “FileOutputStream”
      $s5 = “getParameter”
      $s6 = “new ProcessBuilder”
      $s7 = “new BufferedReader”
      $s8 = “readLine()”
   condition:
      filesize < 15KB and 6 of them
}

 

rule ZimbraImplant {
    strings:
        $u1 = “User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36”
        $u2 = “Content-Type: application/soap+xml; charset=UTF-8”
        $u3 = “/service/soap”
        $u4 = “Good Luck :::)”
        $s1 = “zimBR”
        $s2 = “log10”
        $s3 = “mymain”
        $s4 = “urn:zimbraAccount”
        $s5 = “/service/upload?fmt=extended,raw”
        $s6 = “<query>(in:”inbox” or in:”junk”) is:unread</query>”
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and filesize < 2MB and 1 of ($u*) and 3 of ($s*)
}

 

rule GodzillaDropper {
    strings:
        $s1 = “UEsDBAoAAAAAAI8UXFM” // base64 encoded PK/ZIP header
        $s2 = “../lib/tomcat/tomcat-postgres.jar”
        $s3 = “RunAsManager.exe”
        $s4 = “ServiceDesk”
        $s5 = “C:\Users\pwn\documents\visual studio 2015\Projects\payloaddll”
        $s6 = “CreateMutexA”
        $s7 = “cplusplus_me”
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and filesize < 350KB and 4 of them
}

 

rule GodzillaJAR {
    strings:
        $s1 = “org/apache/tomcat/SSLFilter.class”
        $s2 = “META-INF/services/javax.servlet.ServletContainerInitializer”
        $s3 = “org/apache/tomcat/MainFilterInitializer.class”
    condition:
        uint32(0) == 0x04034B50 and filesize < 50KB and all of them
}

 

rule APT_NGLite {
    strings:
        $s1 = “/mnt/hgfs/CrossC2-2.2”
        $s2 = “WHATswrongwithU”
        $s3 = “//seed.nkn.org:”
        $s4 = “Preylistener”
        $s5 = “preyid”
        $s6 = “Www-Authenticate”
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and filesize < 15MB and 4 of them
}

 

rule KDCSponge {
    strings:
        $k1 = “kdcsvc.dll”
        $k2 = “kdccli.dll”
        $k3 = “kdcsvs.dll”
        $f1 = “KerbHashPasswordEx3”
        $f2 = “KerbFreeKey”
        $f3 = “KdcVerifyEncryptedTimeStamp”
        $s1 = “download//symbols//%S//%S//%S” wide
        $s2 = “KDC Service”
        $s3 = “\system.dat”
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and filesize < 1MB and 1 of ($k*) and 1 of ($f*) and 1 of ($s*)

Mitigations

Compromise Mitigations

Organizations that identify any activity related to ManageEngine ServiceDesk Plus indicators of compromise within their networks should take action immediately. 

Zoho ManageEngine ServiceDesk Plus build 11306, or higher, fixes CVE-2021-44077. ManageEngine initially released a patch for this vulnerability on September 16, 2021. A subsequent security advisory was released on November 22, 2021, and advised customers to patch immediately. Additional information can be found in the Zoho security advisory released on November 22, 2021.

In addition, Zoho has set up a security response plan center that provides additional details, a downloadable tool that can be run on potentially affected systems, and a remediation guide.

FBI and CISA also strongly recommend domain-wide password resets and double Kerberos TGT password resets if any indication is found that the NTDS.dit file was compromised. 

Note: Implementing these password resets should not be taken as a comprehensive mitigation in response to this threat; additional steps may be necessary to regain administrative control of your network. Refer to your specific products mitigation guidance for details. 

Actions for Affected Organizations

Immediately report as an incident to CISA or the FBI (refer to Contact information section below) the existence of any of the following:

  • Identification of indicators of compromise as outlined above.
  • Presence of webshell code on compromised ServiceDesk Plus servers.
  • Unauthorized access to or use of accounts.
  • Evidence of lateral movement by malicious actors with access to compromised systems.
  • Other indicators of unauthorized access or compromise.

Contact Information

Recipients of this report are encouraged to contribute any additional information that they may have related to this threat. 

For any questions related to this report or to report an intrusion and request resources for incident response or technical assistance, please contact:

Revisions

December 2, 2021: Initial version

Source…

Iranian Government-Sponsored APT Cyber Actors Exploiting Microsoft Exchange and Fortinet Vulnerabilities in Furtherance of Malicious Activities


Summary

Actions to Take Today to Protect Against Iranian State-Sponsored Malicious Cyber Activity
• Immediately patch software affected by the following vulnerabilities: CVE-2021-34473, 2018-13379, 2020-12812, and 2019-5591.

Implement
multi-factor authentication.
• Use strong, unique passwords.

Note: this advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, version 10. See the ATT&CK for Enterprise for all referenced threat actor tactics and techniques.

This joint cybersecurity advisory is the result of an analytic effort among the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), the Australian Cyber Security Centre (ACSC), and the United Kingdom’s National Cyber Security Centre (NCSC) to highlight ongoing malicious cyber activity by an advanced persistent threat (APT) group that FBI, CISA, ACSC, and NCSC assess is associated with the government of Iran. FBI and CISA have observed this Iranian government-sponsored APT group exploit Fortinet vulnerabilities since at least March 2021 and a Microsoft Exchange ProxyShell vulnerability since at least October 2021 to gain initial access to systems in advance of follow-on operations, which include deploying ransomware. ACSC is also aware this APT group has used the same Microsoft Exchange vulnerability in Australia.

The Iranian government-sponsored APT actors are actively targeting a broad range of victims across multiple U.S. critical infrastructure sectors, including the Transportation Sector and the Healthcare and Public Health Sector, as well as Australian organizations. FBI, CISA, ACSC, and NCSC assess the actors are focused on exploiting known vulnerabilities rather than targeting specific sectors. These Iranian government-sponsored APT actors can leverage this access for follow-on operations, such as data exfiltration or encryption, ransomware, and extortion.

This advisory provides observed tactics and techniques, as well as indicators of compromise (IOCs) that FBI, CISA, ACSC, and NCSC assess are likely associated with this Iranian government-sponsored APT activity.

The FBI, CISA, ACSC, and NCSC urge critical infrastructure organizations to apply the recommendations listed in the Mitigations section of this advisory to mitigate risk of compromise from Iranian government-sponsored cyber actors.

For more information on Iranian government-sponsored malicious cyber activity, see us-cert.cisa.gov/Iran.

Click here for a PDF version of this report.

Technical Details

Threat Actor Activity

Since at least March 2021, the FBI and CISA have observed Iranian government-sponsored APT actors leverage Microsoft Exchange and Fortinet vulnerabilities to target a broad range of victims across multiple critical infrastructure sectors in furtherance of malicious activities. Observed activity includes the following.

ACSC considers that this APT group has also used the same Microsoft Exchange vulnerability (CVE-2021-34473) in Australia.

MITRE ATT&CK Tactics and Techniques

FBI, CISA, ACSC, and NCSC assess the following tactics and techniques are associated with this activity.

Resource Development [TA0042]

The APT actors have used the following malicious and legitimate tools [T1588.001, T1588.002] for a variety of tactics across the enterprise spectrum.

  • Mimikatz for credential theft [TA0006]
  • WinPEAS for privilege escalation [TA0004]
  • SharpWMI (Windows Management Instrumentation)
  • WinRAR for archiving collected data [TA0009, T1560.001]
  • FileZilla for transferring files [TA0010]

Initial Access [TA0001]

The Iranian government-sponsored APT actors gained initial access by exploiting vulnerabilities affecting Microsoft Exchange servers (CVE-2021-34473) and Fortinet devices (CVE-2018-13379, CVE-2020-12812, and CVE-2019-5591) [T1190].

Execution [TA0002]

The Iranian government-sponsored APT actors may have made modifications to the Task Scheduler [T1053.005]. These modifications may display as unrecognized scheduled tasks or actions. Specifically, the below established tasks may be associated with this activity:

  • SynchronizeTimeZone
  • GoogleChangeManagement
  • MicrosoftOutLookUpdater
  • MicrosoftOutLookUpdateSchedule

Persistence [TA0003]

The Iranian government-sponsored APT actors may have established new user accounts on domain controllers, servers, workstations, and active directories [T1136.001, T1136.002]. Some of these accounts appear to have been created to look similar to other existing accounts on the network, so specific account names may vary per organization. In addition to unrecognized user accounts or accounts established to masquerade as existing accounts, the following account usernames may be associated with this activity:

  • Support
  • Help
  • elie
  • WADGUtilityAccount

Exfiltration [TA0010]

The FBI and CISA observed outbound File Transfer Protocol (FTP) transfers over port 443.

Impact [TA0040]

The APT actors forced BitLocker activation on host networks to encrypt data [T1486]. The corresponding threatening notes were either sent to the victim or left on the victim network as a .txt file. The ransom notes included ransom demands and the following contact information. 

  • sar_addr@protonmail[.]com
  • WeAreHere@secmail[.]pro
  • nosterrmann@mail[.]com
  • nosterrmann@protonmail[.]com 

Detection

The FBI, CISA, ACSC, and NCSC recommend that organizations using Microsoft Exchange servers and Fortinet investigate potential suspicious activity in their networks. 

  • Search for IOCs. Collect known-bad IOCs and search for them in network and host artifacts. Note: refer to Appendix A for IOCs.
  • Investigate exposed Microsoft Exchange servers (both patched and unpatched) for compromise. 
  • Investigate changes to Remote Desktop Protocol (RDP), firewall, and Windows Remote Management (WinRM) configurations that may allow attackers to maintain persistent access. 
  • Review domain controllers, servers, workstations, and active directories for new or unrecognized user accounts.
  • Review Task Scheduler for unrecognized scheduled tasks. Additionally, manually review operating-system defined or recognized scheduled tasks for unrecognized “actions” (for example, review the steps each scheduled task is expected to perform).
  • Review antivirus logs for indications they were unexpectedly turned off.
  • Look for WinRAR and FileZilla in unexpected locations. 

Note: for additional approaches on uncovering malicious cyber activity, see joint advisory Technical Approaches to Uncovering and Remediating Malicious Activity, authored by CISA and the cybersecurity authorities of Australia, Canada, New Zealand, and the United Kingdom. 

Mitigations

The FBI, CISA, ACSC, and NCSC urge network defenders to apply the following mitigations to reduce the risk of compromise by this threat.

Patch and Update Systems

  • Install updates/patch operating systems, software, and firmware as soon as updates/patches are released. 
  • Immediately patch software affected by vulnerabilities identified in this advisory: CVE-2021-34473, CVE-2018-13379, CVE-2020-12812, and CVE-2019-5591.

Evaluate and Update Blocklists and Allowlists

  • Regularly evaluate and update blocklists and allowlists.
  • If FortiOS is not used by your organization, add the key artifact files used by FortiOS to your organization’s execution blocklist. Any attempts to install or run this program and its associated files should be prevented.

Implement and Enforce Backup and Restoration Policies and Procedures

  • Regularly back up data, air gap, and password protect backup copies offline.
  • Ensure copies of critical data are not accessible for modification or deletion from the system where the data resides. 
  • Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, secure location (e.g., hard drive, storage device, the cloud). 

Implement Network Segmentation

  • Implement network segmentation to restrict adversary’s lateral movement. 

Secure User Accounts

  • Audit user accounts with administrative privileges and configure access controls under the principles of least privilege and separation of duties. 
  • Require administrator credentials to install software. 

Implement Multi-Factor Authentication

  • Use multifactor authentication where possible, particularly for webmail, virtual private networks (VPNs), and accounts that access critical systems. 

Use Strong Passwords

  • Require all accounts with password logins to have strong, unique passwords.

Secure and Monitor RDP and other Potentially Risky Services

  • If you use RDP, restrict it to limit access to resources over internal networks.
  • Disable unused remote access/RDP ports.
  • Monitor remote access/RDP logs. 

Use Antivirus Programs

  • Install and regularly update antivirus and anti-malware software on all hosts. 

Secure Remote Access

  • Only use secure networks and avoid using public Wi-Fi networks. 
  • Consider installing and using a VPN for remote access.

Reduce Risk of Phishing

  • Consider adding an email banner to emails received from outside your organization.
  • Disable hyperlinks in received emails

Resources

  • For more information on Iranian government-sponsored malicious cyber activity, see us-cert.cisa.gov/Iran
  • For information and resources on protecting against and responding to ransomware, refer to StopRansomware.gov, a centralized, whole-of-government webpage providing ransomware resources and alerts.
  • The joint advisory from the cybersecurity authorities of Australia, Canada, New Zealand, the United Kingdom, and the United States: Technical Approaches to Uncovering and Remediating Malicious Activity provides additional guidance when hunting or investigating a network and common mistakes to avoid in incident handling.
  • CISA offers a range of no-cost cyber hygiene services to help critical infrastructure organizations assess, identify, and reduce their exposure to threats, including ransomware. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate attack vectors.
  • The U.S. Department of State’s Rewards for Justice (RFJ) program offers a reward of up to $10 million for reports of foreign government malicious activity against U.S. critical infrastructure. See the RFJ website for more information and how to report information securely.
  • ACSC can provide tailored cyber security advice and assistance, reporting, and incident response support at cyber.gov.au and via 1300 292 371 (1300 CYBER1).

Appendix A: Indicators of Compromise

IP addresses and executables files are listed below.

IP Addresses

  • 91.214.124[.]143 
  • 162.55.137[.]20 
  • 154.16.192[.]70

Executable Files 

Executable files observed in this activity are identified in table 1.

Table 1: Executable Files 

Filename: MicrosoftOutLookUpdater[.]exe 
MD5: 1444884faed804667d8c2bfa0d63ab13
SHA-1: 95E045446EFB8C9983EBFD85E39B4BE5D92C7A2A
SHA-256: c51fe5073bd493c7e8d83365aace3f9911437a0f2ae80042ba01ea46b55d2624
SHA-512: 6451077B99C5F8ECC5C0CA88FE272156296BEB91218B39AE28A086DBA5E7E39813F044F9AF0FEDBB260941B1CD52FA237C098CBF4B2A822F08E3E98E934D0ECF
Filename: MicrosoftOutlookUpdater.bat
MD5: 1A44368EB5BF68688BA4B4357BDC874F
SHA-1 FA36FEBFD5A5CA0B3A1B19005B952683A7188A13
SHA-256 3A08D0CB0FF4D95ED0896F22F4DA8755525C243C457BA6273E08453E0E3AC4C4
SHA-512 70AA89449EB5DA1D84B70D114EF9D24CB74751CE12D12C783251E51775C89FDCE61B4265B43B1D613114D6A85E9C75927B706F39C576DBB036079C7E8CAF28B2
Filename: MicrosoftOutlookUpdater.xml
MD5: AA40C49E309959FA04B7E5AC111BB770
SHA-1 F1D90E10E6E3654654E0A677763C9767C913F8F0
SHA-256 5C818FE43F05F4773AD20E0862280B0D5C66611BB12459A08442F55F148400A6
SHA-512 E55A86159F2E869DCDB64FDC730DA893718E20D65A04071770BD32CAE75FF8C34704BDF9F72EF055A3B362759EDE3682B3883C4D9BCF87013076638664E8078E
Filename: GoogleChangeManagement.xml
MD5: AF2D86042602CBBDCC7F1E8EFA6423F9
SHA-1 CDCD97F946B78831A9B88B0A5CD785288DC603C1
SHA-256 4C691CCD811B868D1934B4B8E9ED6D5DB85EF35504F85D860E8FD84C547EBF1D
SHA-512 6473DAC67B75194DEEAEF37103BBA17936F6C16FFCD2A7345A5A46756996FAD748A97F36F8FD4BE4E1F264ECE313773CC5596099D68E71344D8135F50E5D8971
Filename: Connector3.exe
MD5: e64064f76e59dea46a0768993697ef2f
Filename: Audio.exe or frpc.exe
MD5: b90f05b5e705e0b0cb47f51b985f84db
SHA-1 5bd0690247dc1e446916800af169270f100d089b
SHA-256: 28332bdbfaeb8333dad5ada3c10819a1a015db9106d5e8a74beaaf03797511aa
Vhash: 017067555d5d15541az28!z
Authentihash: ed463da90504f3adb43ab82044cddab8922ba029511da9ad5a52b8c20bda65ee
Imphash: 93a138801d9601e4c36e6274c8b9d111
SSDEEP: 98304:MeOuFco2Aate8mjOaFEKC8KZ1F4ANWyJXf/X+g4:MeHFV2AatevjOaDC8KZ1xNWy93U
Note:

Identical to “frpc.exe” available at:

https://github[.]com/fatedier/frp/releases/download/v0.34.3/frp_0.34.3_windows_amd64.zip

Filename: Frps.exe
MD5: 26f330dadcdd717ef575aa5bfcdbe76a
SHA-1 c4160aa55d092cf916a98f3b3ee8b940f2755053
SHA-256: d7982ffe09f947e5b4237c9477af73a034114af03968e3c4ce462a029f072a5a
Vhash: 017057555d6d141az25!z
Authentihash: 40ed1568fef4c5f9d03c370b2b9b06a3d0bd32caca1850f509223b3cee2225ea
Imphash: 91802a615b3a5c4bcc05bc5f66a5b219
SSDEEP: 196608:/qTLyGAlLrOt8enYfrhkhBnfY0NIPvoOQiE:GLHiLrSfY5voO
Note:

Identical to “frps.exe” available at: 

https://github[.]com/fatedier/frp/releases/download/v0.33.0/frp_0.33.0_windows_amd64.zip

 

 

APPENDIX B: MITRE ATT&CK TACTICS AND TECHNIQUES

Table 2 identifies MITRE ATT&CK Tactics and techniques observed in this activity.

Table 2: Observed Tactics and Techniques

Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at https://www.fbi.gov/contact-us/field-offices, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at [email protected]. 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. To request incident response resources or technical assistance related to these threats, contact CISA at [email protected]. Australian organizations can visit cyber.gov.au or call 1300 292 371 (1300 CYBER 1) to report cybersecurity incidents and access alerts and advisories.

Revisions

Initial Version: November 17, 2021

Source…

BlackMatter Ransomware | CISA


Summary

Actions You Can Take Now to Protect Against BlackMatter Ransomware
• Implement and enforce backup and restoration policies and procedures.

Use
strong, unique passwords.
Use multi-factor authentication.
• Implement network segmentation and traversal monitoring.

Note: this advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, version 9. See the ATT&CK for Enterprise for all referenced threat actor tactics and techniques.

This joint Cybersecurity Advisory was developed by the Cybersecurity and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), and the National Security Agency (NSA) to provide information on BlackMatter ransomware. Since July 2021, BlackMatter ransomware has targeted multiple U.S. critical infrastructure entities, including two U.S. Food and Agriculture Sector organizations.

This advisory provides information on cyber actor tactics, techniques, and procedures (TTPs) obtained from a sample of BlackMatter ransomware analyzed in a sandbox environment as well from trusted third-party reporting. Using embedded, previously compromised credentials, BlackMatter leverages the Lightweight Directory Access Protocol (LDAP) and Server Message Block (SMB) protocol to access the Active Directory (AD) to discover all hosts on the network. BlackMatter then remotely encrypts the hosts and shared drives as they are found.

Ransomware attacks against critical infrastructure entities could directly affect consumer access to critical infrastructure services; therefore, CISA, the FBI, and NSA urge all organizations, including critical infrastructure organizations, to implement the recommendations listed in the Mitigations section of this joint advisory. These mitigations will help organizations reduce the risk of compromise from BlackMatter ransomware attacks.

Click here for a PDF version of this report.

Technical Details

Overview

First seen in July 2021, BlackMatter is ransomware-as-a-service (Raas) tool that allows  the ransomware’s developers to profit from cybercriminal affiliates (i.e., BlackMatter actors) who deploy it against victims. BlackMatter is a possible rebrand of DarkSide, a RaaS which was active from September 2020 through May 2021. BlackMatter actors have attacked numerous U.S.-based organizations and have demanded ransom payments ranging from $80,000 to $15,000,000 in Bitcoin and Monero.

Tactics, Techniques, and Procedures

This advisory provides information on cyber actor TTPs obtained from the following sample of BlackMatter ransomware, which was analyzed in a sandbox environment, as well as from trusted third parties: SHA-256: 706f3eec328e91ff7f66c8f0a2fb9b556325c153a329a2062dc85879c540839d. (Note: click here to see the sample’s page on VirusTotal.)

The BlackMatter variant uses embedded admin or user credentials that were previously compromised and NtQuerySystemInformation and EnumServicesStatusExW to enumerate running processes and services, respectively. BlackMatter then uses the embedded credentials in the LDAP and SMB protocol to discover all hosts in the AD and the srvsvc.NetShareEnumAll Microsoft Remote Procedure Call (MSRPC) function to enumerate each host for accessible shares. Notably, this variant of BlackMatter leverages the embedded credentials and SMB protocol to remotely encrypt, from the original compromised host, all discovered shares’ contents, including ADMIN$, C$, SYSVOL, and NETLOGON.

BlackMatter actors use a separate encryption binary for Linux-based machines and routinely encrypt ESXi virtual machines. Rather than encrypting backup systems, BlackMatter actors wipe or reformat backup data stores and appliances.

Table 1 maps BlackMatter’s capabilities to the MITRE ATT&CK for Enterprise framework, based on the analyzed variant and trusted third-party reporting.

Table 1: Black Matter Actors and Ransomware TTPs

Tactic

Technique 

Procedure 

Persistence [TA0003]

External Remote Services [T1133]

BlackMatter leverages legitimate remote monitoring and management software and remote desktop software, often by setting up trial accounts, to maintain persistence on victim networks. 

Credential Access [TA0006]

OS Credential Dumping: LSASS Memory [T1003.001]

BlackMatter harvests credentials from Local Security Authority Subsystem Service (LSASS) memory using procmon.

Discovery [TA0007]

Remote System Discovery [T1018]

BlackMatter leverages LDAP and SMB protocol to discover all hosts in the AD.

Process Discovery [T1057]

BlackMatter uses NtQuerySystemInformation to enumerate running processes.

System Service Discovery [T1007]

BlackMatter uses EnumServicesStatusExW to enumerate running services on the network.

Lateral Movement [TA0008]

Remote Services: SMB/Windows Admin Shares [T1021.002]

BlackMatter uses srvsvc.NetShareEnumAll MSRPC function to enumerate and SMB to connect to all discovered shares, including ADMIN$, C$, SYSVOL, and NETLOGON.

Exfiltration [TA0010]

Exfiltration Over Web Service [T1567]

BlackMatter attempts to exfiltrate data for extortion.

Impact [TA0040]

Data Encrypted for Impact [T1486]

BlackMatter remotely encrypts shares via SMB protocol and drops a ransomware note in each directory.

Disk Wipe [T1561]

BlackMatter may wipe backup systems.

Detection Signatures

The following Snort signatures may be used for detecting network activity associated with BlackMatter activity.

Intrusion Detection System Rule:

alert tcp any any -> any 445 ( msg:"BlackMatter remote encryption attempt";  content:"|01 00 00 00 00 00 05 00 01 00|";  content:"|2e 00 52 00 45 00 41 00 44 00 4d 00 45 00 2e 00 74 00|"; distance:100; detection_filter: track by_src, count 4, seconds 1; priority:1; sid:11111111111; )

Inline Intrusion Prevention System Rule:

alert tcp any any -> any 445 ( msg:"BlackMatter remote encryption attempt";  content:"|01 00 00 00 00 00 05 00 01 00|";  content:"|2e 00 52 00 45 00 41 00 44 00 4d 00 45 00 2e 00 74 00|"; distance:100; priority:1; sid:10000001; )

rate_filter gen_id 1, sig_id 10000001, track by_src, count 4, seconds 1, new_action reject, timeout 86400

Mitigations

CISA, the FBI, and NSA urge network defenders, especially for critical infrastructure organizations, to apply the following mitigations to reduce the risk of compromise by BlackMatter ransomware:

Implement Detection Signatures

  • Implement the detection signatures identified above. These signatures will identify and block placement of the ransom note on the first share that is encrypted, subsequently blocking additional SMB traffic from the encryptor system for 24 hours. 

Use Strong Passwords

Implement Multi-Factor Authentication

Patch and Update Systems

  • Keep all operating systems and software 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.

Limit Access to Resources over the Network

  • Remove unnecessary access to administrative shares, especially ADMIN$ and C$. If ADMIN$ and C$ are deemed operationally necessary, restrict privileges to only the necessary service or user accounts and perform continuous monitoring for anomalous activity.
  • Use a host-based firewall to only allow connections to administrative shares via SMB from a limited set of administrator machines. 

Implement Network Segmentation and Traversal Monitoring

Adversaries use system and network discovery techniques for network and system visibility and mapping. To limit an adversary from learning the organization’s enterprise environment, limit common system and network discovery techniques by taking the following actions.

  • 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. 
  • 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. 

Use Admin Disabling Tools to Support Identity and Privileged Access Management

If BlackMatter uses compromised credentials during non-business hours, the compromise may not be detected. Given that there has been an observed increase in ransomware attacks during non-business hours, especially holidays and weekends, CISA, the FBI, and NSA recommend organizations:

  • 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 AD level when the account is not in direct need. When the account is needed, individual users submit their requests through an automated process that enables access to a system, but only for a set timeframe to support task completion. 
  • Disable command-line and scripting activities and permissions. Privilege escalation and lateral movement often depend on software utilities that run from the command line. If threat actors are not able to run these tools, they will have difficulty escalating privileges and/or moving laterally. 

Implement and Enforce Backup and Restoration Policies and Procedures

  • Maintain offline backups of data, and regularly maintain backup and restoration. This practice will ensure the organization will not be severely interrupted, have irretrievable data, or be held up by a ransom demand.
  • Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted) and covers the entire organization’s data infrastructure. 

CISA, the FBI, and NSA urge critical infrastructure organizations to apply the following additional mitigations to reduce the risk of credential compromise.

  • Disable the storage of clear text passwords in LSASS memory.
  • Consider disabling or limiting New Technology Local Area Network Manager (NTLM) and WDigest Authentication.
  • Implement Credential Guard for Windows 10 and Server 2016 (Refer to Microsoft: Manage Windows Defender Credential Guard for more information). For Windows Server 2012R2, enable Protected Process Light for Local Security Authority (LSA). 
  • Minimize the AD attack surface to reduce malicious ticket-granting activity. Malicious activity such as “Kerberoasting” takes advantage of Kerberos’ Ticket Granting service and can be used to obtain hashed credentials that attackers attempt to crack.
    • Set a strong password policy for service accounts.
    • Audit Domain Controllers to log successful Kerberos Ticket-Granting Service requests and ensure the events are monitored for anomalous activity.  

Refer to the CISA-Multi-State information and Sharing Center (MS-ISAC) Joint Ransomware Guide for general mitigations to prepare for and reduce the risk of compromise by ransomware attacks. 

Note: critical infrastructure organizations with industrial control systems/operational technology networks should review joint CISA-FBI Cybersecurity Advisory AA21-131A: DarkSide Ransomware: Best Practices for Preventing Business Disruption from Ransomware Attacks for more mitigations, including mitigations to reduce the risk of severe business or functional degradation should their entity fall victim to a ransomware attack. 

Responding to Ransomware Attacks

If a ransomware incident occurs at your organization, CISA, the FBI, and NSA recommend:

Note: CISA, the FBI, and NSA strongly discourage paying a ransom to criminal actors. Paying a ransom may embolden adversaries to target additional organizations, encourage other criminal actors to engage in the distribution of ransomware, and/or may fund illicit activities. Paying the ransom also does not guarantee that a victim’s files will be recovered.

Resources

  • For more information and resources on protecting against and responding to ransomware, refer to StopRansomware.gov, a centralized, whole-of-government webpage providing ransomware resources and alerts.
  • CISA’s Ransomware Readiness Assessment (RRA) is a no-cost self-assessment based on a tiered set of practices to help organizations better assess how well they are equipped to defend and recover from a ransomware incident. 
  • CISA offers a range of no-cost cyber hygiene services to help critical infrastructure organizations assess, identify, and reduce their exposure to threats, including ransomware. By requesting these services, organizations of any size could find ways to reduce their risk and mitigate attack vectors.

Contact Information

Victims of ransomware should report it immediately to CISA at us-cert.cisa.gov/report, a local FBI Field Office, or U.S. Secret Service 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 the NSA Cybersecurity Requirements Center at 410-854-4200 or [email protected].

This document was developed by CISA, the FBI, and NSA in furtherance of their respective cybersecurity missions, including their responsibilities to develop and issue cybersecurity specifications and mitigations.

Note: the information you have accessed is being provided “as is” for informational purposes only. CISA, the FBI, and NSA do 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 their endorsement, recommendation, or favoring by CISA, the FBI, or NSA.

Revisions

October 18, 2021: Initial Version

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