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This report is provided “as is” for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained herein. The DHS does not endorse any commercial product or service referenced in this bulletin or otherwise.

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 (TLP), see http://www.us-cert.gov/tlp.

Description

This Malware Analysis Report (MAR) is the result of analytic efforts between the Department of Homeland Security (DHS), the Federal Bureau of Investigation (FBI), and the Department of Defense (DoD). Working with U.S. Government partners, DHS, FBI, and DoD identified Remote Access Tool (RAT) malware variants used by the North Korean government. This malware variant has been identified as VIVACIOUSGIFT. The U.S. Government refers to malicious cyber activity by the North Korean government as HIDDEN COBRA. For more information on HIDDEN COBRA activity, visit https[:]//www[.]us-cert.gov/hiddencobra.

FBI has high confidence that HIDDEN COBRA actors are using malware variants in conjunction with proxy servers to maintain a presence on victim networks and to further network exploitation. DHS, FBI, and DoD are distributing this MAR to enable network defense and reduce exposure to North Korean government malicious cyber activity.

This MAR includes malware descriptions related to HIDDEN COBRA, suggested response actions and recommended mitigation techniques. Users or administrators should flag activity associated with the malware and report the activity to the Cybersecurity and Infrastructure Security Agency (CISA) or the FBI Cyber Watch (CyWatch), and give the activity the highest priority for enhanced mitigation.

This report looks at the malware samples known as VIVACIOUSGIFT that is used by advanced persistent threat (APT) cyber actors as a network proxy tool. The proxy requires an encrypted command line argument for its source and destination Internet Protocol (IP) addresses and has command and control (C2) functionality to retrieve and set the destination IP. The command line argument can also contain a source proxy IP, port, and password. The source proxy is used as an additional proxy when communicating with the source IP. The library libcurl version 7.94.1 is used when communicating with the source proxy.

For a downloadable copy of IOCs, see MAR-10301706-2.v1.stix.

Submitted Files (6)

70b494b0a8fdf054926829dcb3235fc7bd0346b6a19faf2a57891c71043b3b38 (70b494b0a8fdf054926829dcb3235f…)

8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1 (8cad61422d032119219f465331308c…)

9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852 (9a776b895e93926e2a758c09e341ac…)

a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118 (a917c1cc198cf36c0f2f6c24652e5c…)

aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83 (aca598e2c619424077ef8043cb4284…)

f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de (f3ca8f15ca582dd486bd78fd57c2f4…)

a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118

Tags

HIDDEN-COBRAproxytrojan

Details

Antivirus

YARA Rules

• rule CISA_3P_10301706_02 : HiddenCobra TWOPENCE backdoor dropper proxy spyware trojan
  {
     meta:
         Author = “CISA Trusted Third Party”
         Incident = “10301706.r2.v1”
         Date = “2020-08-11”
         Actor = “Hidden Cobra”
         Category = “Backdoor Dropper Proxy Spyware Trojan”
         Family = “TWOPENCE”
         Description = “Detects strings in TWOPENCE proxy tool”
         MD5_1 = “40e698f961eb796728a57ddf81f52b9a”
         SHA256_1 = “a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118”
         MD5_2 = “dfd09e91b7f86a984f8687ed6033af9d”
         SHA256_2 = “aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83”
         MD5_3 = “bda82f0d9e2cb7996d2eefdd1e5b41c4”
         SHA256_3 = “f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de”
         MD5_4 = “97aaf130cfa251e5207ea74b2558293d”
         SHA256_4 = “9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852”
         MD5_5 = “889e320cf66520485e1a0475107d7419”
         SHA256_5 = “8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1”
     strings:
         $cmd1 = “ssylka”
         $cmd2 = “ustanavlivat”
         $cmd3 = “poluchit”
         $cmd4 = “pereslat”
         $cmd5 = “derzhat”
         $cmd6 = “vykhodit”
         $cmd7 = “Nachalo”
         $cmd8 = “kliyent2podklyuchit”
         $frmt1 = “Host: %s%s%s:%hu”
         $frmt2 = “%s%s%s%s%s%s%s%s%s%s”
     condition:
         (4 of ($cmd*)) and (1 of ($frmt*))
  }

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Description

This file is a 32-bit Windows executable. The proxy requires a single command line argument. The argument can consist of a maximum of four encrypted strings delineated with the pipe character (“|”). When the four strings are parsed and decrypted, the strings represent the following: source IP and port, destination IP and port, source proxy IP and port, and source proxy password. The IP and port strings have the following format: <IP:port>. If the destination IP is missing from the command line argument, the proxy will wait to get the destination IP from the actor. The source proxy IP and port, as well as the source proxy password, are used as an additional proxy when communicating with the source IP. When communicating with the source proxy, the proxy will use libcurl with the options CURLOPT_HTTPPROXYTUNNEL and CURLOPT_NOBODY.

The following is an example of an encrypted command line argument that is missing the destination IP:

–Begin encrypted command line argument–
<encrypted_string>| |<encrypted_string>|<encrypted_string>
–End encrypted command line argument–

–Begin decrypted command line argument–
<IP>:<port>| |<IP>:<port>|<password>
–End decrypted command line argument–

The encrypted strings inside the command line argument can be individually decrypted with the Python script provided in Figure 1.

Below is the flow of events that happens when the proxy starts and is issued the commands “ustanavlivat” and “pereslat”. In the following example, the command line argument does not contain a source proxy. The command line argument can contain a source proxy IP, port, and password. If they exist, the proxy will route all traffic to the source IP through the source proxy. When communicating with the source proxy, the proxy uses the library libcurl with options CURLOPT_HTTPPROXYTUNNEL and CURLOPT_NOBODY. The data that is sent and received is encrypted using a custom encryption routine.

First, it connects to source IP and sends initialization message “Nachalo”. It sends a custom hash of “Dazdrav$958478Zohsf9q@%5555ahshdnZXniohs”. In return it receives two bytes of data. It sends the length (4 bytes) of string “kliyent2podklyuchit” and then sends the string “kliyent2podklyuchit”. It sends the length (4 bytes) of string “Nachalo” and then sends the “Nachalo”.

Next, it receives C2 command “ustanavlivat” to set the destination IP address. It receives and decrypts the length of the string “ustanavlivat” and then receives and decrypts the string “ustanavlivat”.

Then, it receives C2 command “pereslat” to start the proxy functionality. It receives and decrypts the length of the string “pereslat” and then receives and decrypts the string “pereslat”.

Next, it connects to source IP and sends start proxy functionality message “ssylka”. It sends a custom hash of “Dazdrav$958478Zohsf9q@%5555ahshdnZXniohs”. In response it receives data. Then it sends the length (4 bytes) of string “kliyent2podklyuchit” and then sends the string “kliyent2podklyuchit”. Then it sends the length (4 bytes) of string “ssylka” and then sends the string “ssylka”.

Finally, it connects to destination IP and starts proxy functionality between source and destination IP.

The proxy uses a custom encryption routine to encode the data sent. The Python script provided in Figure 2 can decode the data.

Screenshots

aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83

Tags

HIDDEN-COBRAdropperproxyspywaretrojan

Details

Antivirus

YARA Rules

• rule CISA_3P_10301706_02 : HiddenCobra TWOPENCE backdoor dropper proxy spyware trojan
  {
     meta:
         Author = “CISA Trusted Third Party”
         Incident = “10301706.r2.v1”
         Date = “2020-08-11”
         Actor = “Hidden Cobra”
         Category = “Backdoor Dropper Proxy Spyware Trojan”
         Family = “TWOPENCE”
         Description = “Detects strings in TWOPENCE proxy tool”
         MD5_1 = “40e698f961eb796728a57ddf81f52b9a”
         SHA256_1 = “a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118”
         MD5_2 = “dfd09e91b7f86a984f8687ed6033af9d”
         SHA256_2 = “aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83”
         MD5_3 = “bda82f0d9e2cb7996d2eefdd1e5b41c4”
         SHA256_3 = “f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de”
         MD5_4 = “97aaf130cfa251e5207ea74b2558293d”
         SHA256_4 = “9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852”
         MD5_5 = “889e320cf66520485e1a0475107d7419”
         SHA256_5 = “8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1”
     strings:
         $cmd1 = “ssylka”
         $cmd2 = “ustanavlivat”
         $cmd3 = “poluchit”
         $cmd4 = “pereslat”
         $cmd5 = “derzhat”
         $cmd6 = “vykhodit”
         $cmd7 = “Nachalo”
         $cmd8 = “kliyent2podklyuchit”
         $frmt1 = “Host: %s%s%s:%hu”
         $frmt2 = “%s%s%s%s%s%s%s%s%s%s”
     condition:
         (4 of ($cmd*)) and (1 of ($frmt*))
  }

ssdeep Matches

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Description

This file is a 32-bit Windows executable. It has similar functionality as a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118.

f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de

Tags

HIDDEN-COBRAproxytrojan

Details

Antivirus

YARA Rules

• rule CISA_3P_10301706_02 : HiddenCobra TWOPENCE backdoor dropper proxy spyware trojan
  {
     meta:
         Author = “CISA Trusted Third Party”
         Incident = “10301706.r2.v1”
         Date = “2020-08-11”
         Actor = “Hidden Cobra”
         Category = “Backdoor Dropper Proxy Spyware Trojan”
         Family = “TWOPENCE”
         Description = “Detects strings in TWOPENCE proxy tool”
         MD5_1 = “40e698f961eb796728a57ddf81f52b9a”
         SHA256_1 = “a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118”
         MD5_2 = “dfd09e91b7f86a984f8687ed6033af9d”
         SHA256_2 = “aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83”
         MD5_3 = “bda82f0d9e2cb7996d2eefdd1e5b41c4”
         SHA256_3 = “f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de”
         MD5_4 = “97aaf130cfa251e5207ea74b2558293d”
         SHA256_4 = “9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852”
         MD5_5 = “889e320cf66520485e1a0475107d7419”
         SHA256_5 = “8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1”
     strings:
         $cmd1 = “ssylka”
         $cmd2 = “ustanavlivat”
         $cmd3 = “poluchit”
         $cmd4 = “pereslat”
         $cmd5 = “derzhat”
         $cmd6 = “vykhodit”
         $cmd7 = “Nachalo”
         $cmd8 = “kliyent2podklyuchit”
         $frmt1 = “Host: %s%s%s:%hu”
         $frmt2 = “%s%s%s%s%s%s%s%s%s%s”
     condition:
         (4 of ($cmd*)) and (1 of ($frmt*))
  }

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Description

This file is a 64-bit Windows executable. It has similar functionality as a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118.

9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852

Tags

HIDDEN-COBRAproxyspywaretrojan

Details

Antivirus

YARA Rules

• rule CISA_3P_10301706_02 : HiddenCobra TWOPENCE backdoor dropper proxy spyware trojan
  {
     meta:
         Author = “CISA Trusted Third Party”
         Incident = “10301706.r2.v1”
         Date = “2020-08-11”
         Actor = “Hidden Cobra”
         Category = “Backdoor Dropper Proxy Spyware Trojan”
         Family = “TWOPENCE”
         Description = “Detects strings in TWOPENCE proxy tool”
         MD5_1 = “40e698f961eb796728a57ddf81f52b9a”
         SHA256_1 = “a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118”
         MD5_2 = “dfd09e91b7f86a984f8687ed6033af9d”
         SHA256_2 = “aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83”
         MD5_3 = “bda82f0d9e2cb7996d2eefdd1e5b41c4”
         SHA256_3 = “f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de”
         MD5_4 = “97aaf130cfa251e5207ea74b2558293d”
         SHA256_4 = “9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852”
         MD5_5 = “889e320cf66520485e1a0475107d7419”
         SHA256_5 = “8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1”
     strings:
         $cmd1 = “ssylka”
         $cmd2 = “ustanavlivat”
         $cmd3 = “poluchit”
         $cmd4 = “pereslat”
         $cmd5 = “derzhat”
         $cmd6 = “vykhodit”
         $cmd7 = “Nachalo”
         $cmd8 = “kliyent2podklyuchit”
         $frmt1 = “Host: %s%s%s:%hu”
         $frmt2 = “%s%s%s%s%s%s%s%s%s%s”
     condition:
         (4 of ($cmd*)) and (1 of ($frmt*))
  }

ssdeep Matches

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Description

This file is a 32-bit Windows executable. It has similar functionality as a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118.

70b494b0a8fdf054926829dcb3235fc7bd0346b6a19faf2a57891c71043b3b38

Tags

HIDDEN-COBRAbackdoorproxytrojan

Details

Antivirus

YARA Rules

No matches found.

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Description

This file is a 32-bit Windows executable. It has similar functionality as a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118.

8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1

Tags

HIDDEN-COBRAproxyspywaretrojan

Details

Antivirus

YARA Rules

• rule CISA_3P_10301706_02 : HiddenCobra TWOPENCE backdoor dropper proxy spyware trojan
  {
     meta:
         Author = “CISA Trusted Third Party”
         Incident = “10301706.r2.v1”
         Date = “2020-08-11”
         Actor = “Hidden Cobra”
         Category = “Backdoor Dropper Proxy Spyware Trojan”
         Family = “TWOPENCE”
         Description = “Detects strings in TWOPENCE proxy tool”
         MD5_1 = “40e698f961eb796728a57ddf81f52b9a”
         SHA256_1 = “a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118”
         MD5_2 = “dfd09e91b7f86a984f8687ed6033af9d”
         SHA256_2 = “aca598e2c619424077ef8043cb4284729045d296ce95414c83ed70985c892c83”
         MD5_3 = “bda82f0d9e2cb7996d2eefdd1e5b41c4”
         SHA256_3 = “f3ca8f15ca582dd486bd78fd57c2f4d7b958163542561606bebd250c827022de”
         MD5_4 = “97aaf130cfa251e5207ea74b2558293d”
         SHA256_4 = “9a776b895e93926e2a758c09e341accb9333edc1243d216a5e53f47c6043c852”
         MD5_5 = “889e320cf66520485e1a0475107d7419”
         SHA256_5 = “8cad61422d032119219f465331308c5a61e21c9a3a431b88e1f8b25129b7e2a1”
     strings:
         $cmd1 = “ssylka”
         $cmd2 = “ustanavlivat”
         $cmd3 = “poluchit”
         $cmd4 = “pereslat”
         $cmd5 = “derzhat”
         $cmd6 = “vykhodit”
         $cmd7 = “Nachalo”
         $cmd8 = “kliyent2podklyuchit”
         $frmt1 = “Host: %s%s%s:%hu”
         $frmt2 = “%s%s%s%s%s%s%s%s%s%s”
     condition:
         (4 of ($cmd*)) and (1 of ($frmt*))
  }

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Description

This file is a 32-bit Windows executable. It has similar functionality as a917c1cc198cf36c0f2f6c24652e5c2e94e28d963b128d54f00144d216b2d118.

The following Snort rules were provided by a CISA trusted third party:

// The following Snort rule can be used to detect proxy handshake
alert tcp any any -> any any (msg:”Proxy handshake detected”; content:”|a7 00 a7 00 fb 00 b0 00 8e 00 c5 00 b0 00 48 00 17 00 c5 00 8b 00 6a 00 8e 00 ec 00 f3 00 fe 00 d9 00 f3 00 a7 00 6a 00 ec 00 a7 00 b0 00 17 00 fc 00 48 00 48 00 09 00 09 00 09 00 48 00 8e 00 ce|”; rev:1; sid:1;)

// The following Snort rule can be used to detect encrypted proxy string kliyent2podklyuchit
alert tcp any any -> any any (msg:”Proxy string detected”; content:”|d1 14 23 b3 c7 b2 ac fe 70 0d 1c d1 14 b3 d7 f9 38 23 ac|”; rev:1; sid:1;)

// The following Snort rule can be used to detect encrypted proxy string poluchit
alert tcp any any -> any any (msg:”Proxy string detected”; content:”|70 0d 14 d7 f9 38 23 ac|”; rev:1; sid:1;)

// The following Snort rule can be used to detect encrypted proxy string pereslat
alert tcp any any -> any any (msg:”Proxy string detected”; content:”|70 c7 be c7 c9 14 ab ac|”; rev:1; sid:1;)

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization’s systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

• Maintain up-to-date antivirus signatures and engines.
• Keep operating system patches up-to-date.
• Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
• Restrict users’ ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
• Enforce a strong password policy and implement regular password changes.
• Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
• Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
• Disable unnecessary services on agency workstations and servers.
• Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its “true file type” (i.e., the extension matches the file header).
• Monitor users’ web browsing habits; restrict access to sites with unfavorable content.
• Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
• Scan all software downloaded from the Internet prior to executing.
• Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, “Guide to Malware Incident Prevention & Handling for Desktops and Laptops”.

• 1-888-282-0870
• CISA Service Desk (UNCLASS)
• CISA SIPR (SIPRNET)
• CISA IC (JWICS)

CISA continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://www.cisa.gov/forms/feedback/

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the CISA at 1-888-282-0870 or CISA Service Desk.

Can I submit malware to CISA? Malware samples can be submitted via three methods:

• Web: https://malware.us-cert.gov
• E-Mail: submit@malware.us-cert.gov
• FTP: ftp.malware.us-cert.gov (anonymous)

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 CISA’s homepage at www.cisa.gov.