Analysis Report

MAR-10135536-21 – North Korean Proxy Malware: ELECTRICFISH

Last Revised
Alert Code
AR19-252B

Notification

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.

Summary

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 proxy malware variants used by the North Korean government - referred to by the U.S. Government as ELECTRICFISH. 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.

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, report the activity to the DHS National Cybersecurity and Communications Integration Center (NCCIC) or the FBI Cyber Watch (CyWatch), and give the activity the highest priority for enhanced mitigation.

This report provides analysis of two malicious 32-bit Windows executable file. The malware implements a custom protocol that allows traffic to be tunneled between a source and a destination Internet Protocol (IP) address. The malware continuously attempts to reach out to the source and the designation system, which allows either side to initiate a tunneling session. The malware can be configured with a proxy server/port and proxy username and password. This feature allows connectivity to a system sitting inside of a proxy server, which allows the actor to bypass the compromised system’s required authentication to reach outside of the network.

For a downloadable copy of IOCs, see:

Submitted Files (2)

7cf5d86cc75cd8f0e22e35213a9c051b740bd4667d9879a446f06277782bffd1 (0BA6BB2AD05D86207B5303657E3F68...)

a1260fd3e9221d1bc5b9ece6e7a5a98669c79e124453f2ac58625085759ed3bb (8d9123cd2648020292b5c35edc9ae2...)

Findings

a1260fd3e9221d1bc5b9ece6e7a5a98669c79e124453f2ac58625085759ed3bb

Tags

droppertrojan

Details
Name 8d9123cd2648020292b5c35edc9ae22e
Size 1422336 bytes
Type PE32 executable (GUI) Intel 80386, for MS Windows
MD5 8d9123cd2648020292b5c35edc9ae22e
SHA1 0939363ff55d914e92635e5f693099fb28047602
SHA256 a1260fd3e9221d1bc5b9ece6e7a5a98669c79e124453f2ac58625085759ed3bb
SHA512 646697e3d5146e05a221183f6c9f00f5eb38400ef9a2f83bfd0fcf2f8af1a7efff99c0a3486740c745ce6cf0939c4f0678cb818cbbff8ed2b28a703fe8d823bb
ssdeep 24576:HsO8RKL6OLnWZGFbHq0aMow5Q3gkD/74tU3hYPgP5IyrMsEOhVRpxHkADUHEPbzJ:0KjKHMbO3pkoBIyIstVRpxHL1bF
Entropy 6.703195
Antivirus
Ahnlab HackTool/Win32.Agent
Antiy Trojan[Banker]/Win32.Alreay
Avira TR/AD.Stantinko.gkqij
BitDefender Gen:Variant.Ursu.349885Unclassified
ClamAV Win.Dropper.Electricfish-6976665-0
Cyren W32/Trojan.TWUO-7654
ESET a variant of Win32/NukeSped.FQ trojan
Emsisoft Gen:Variant.Ursu.349885 (B)
Ikarus Trojan.Win32.HackTool
K7 Hacktool ( 0054e46d1 )
Kaspersky Trojan.Win32.Agent.xaadtn
McAfee ElectricFish
Microsoft Security Essentials HackTool:Win32/ElecFish.A!dha
NANOAV Trojan.Win32.Alreay.fvrmai
Quick Heal Trojan.Ursu
Sophos Troj/ElecFish-A
Symantec Unavailable (production)
TACHYON Trojan/W32.Electricfish.1422336
VirusBlokAda Trojan.Agent
Zillya! Tool.ElectricFish.Win32.2
Yara Rules
hidden_cobra_consolidated.yara rule electricfish { meta: Author = "CISA trusted 3rd party" Incident = "10135536" Date = "2019-08-14" Category = "Hidden_Cobra" Family = "ELECTRICFISH" Description = "Detects logging functionality" MD5_1 = "0ba6bb2ad05d86207b5303657e3f6874" SHA256_1 = "7cf5d86cc75cd8f0e22e35213a9c051b740bd4667d9879a446f06277782bffd1" strings: $ = "LLgcIP" $ = "CCGC_LOG" $ = "LLGC_LOG" condition: uint16(0) == 0x5a4d and uint16(uint32(0x3c)) == 0x4550 and all of them }
ssdeep Matches

No matches found.

PE Metadata
Compile Date 2018-09-29 11:55:36-04:00
Import Hash 3549cfa19e60aa9239f79d80e19279fa
PE Sections
MD5 Name Raw Size Entropy
08bb17d8e839e7fc92426e813a696e73 header 1024 2.590786
6c3daca3c522ab98a8ac12a45087297c .text 983040 6.595856
3d3d7962d16652002018640a3fa27d44 .rdata 340480 6.187858
b7f382ea7e6c9c8e737cb92551341e64 .data 37888 4.714377
871fb8486e5ea3307ff7b65ddf46518a .rsrc 512 5.112624
382715f8e776a544bf70f843a52e3ff2 .reloc 59392 6.015022
Packers/Compilers/Cryptors
Microsoft Visual C++ ?.?
Description

This file is a malicious Windows 32-bit executable. The application is a command-line utility and its primary purpose is to tunnel traffic between two IP addresses. The application accepts the following command-line arguments, which can be utilized to authenticate with a proxy server:

--Begin command-line arguments--
-l,--log [Show Debug Message]
-pw,--password [Password]
-u,--username [UserName]
-do,--domain [DomainName]
-p,--proxy [ProxyIP:Port]
-d,--destination [TargetIP:Port]
-s,--server [LLgcIP:Port]
-h,--help [Show this help message]
--End command-line arguments--

Displayed below is an example:

--Begin Example Usage--
Source IP/Port: 192.0.2.1:92
Dest IP/Port: 198.51.100.1:92
Proxy IP/Port: 203.0.113.1:92
Proxy User Name: test
Proxy Password: testpw

a12.exe -s 192.0.2.1:92 -d 198.51.100.1:92 -p 203.0.113.1:92 -u test -pw testpw​
--End Example Usage--

It will attempt to establish TCP sessions with the source IP address and the destination IP address. If a connection is made to both the source and destination IPs, this malicious utility will implement a custom protocol, which will allow traffic to rapidly and efficiently be tunneled between two machines. If necessary, the malware can authenticate with a proxy to be able to reach the destination IP address. A configured proxy server is not required for this utility.

After the malware authenticates with the configured proxy, it will immediately attempt to establish a session with the destination IP address, located outside of the target network and the source IP address. The header of the initial authentication packet, sent to both the source and destination systems, will be static except for two random bytes. Everything within this 34-byte header is static except for the bytes 0X2B6E, which will change during each connection attempt. Displayed below (and displayed in Figure 7) is the packet header.

--Begin Authentication Packet Sent to Destination System--
6161616162626262636363636464646400000000000000002B6E0000040000009210
--End Authentication Packet Sent to Destination System--

Screenshots

Figure 1 -

Figure 1 -

Figure 2 -

Figure 2 -

Figure 3 -

Figure 3 -

Figure 4 -

Figure 4 -

Figure 5 -

Figure 5 -

Figure 6 -

Figure 6 -

Figure 7 -

Figure 7 -

7cf5d86cc75cd8f0e22e35213a9c051b740bd4667d9879a446f06277782bffd1

Tags

trojan

Details
Name 0BA6BB2AD05D86207B5303657E3F6874
Size 1436160 bytes
Type PE32 executable (GUI) Intel 80386, for MS Windows
MD5 0ba6bb2ad05d86207b5303657e3f6874
SHA1 ad44567c8709df4889d381a0a64cc4b49e5004c3
SHA256 7cf5d86cc75cd8f0e22e35213a9c051b740bd4667d9879a446f06277782bffd1
SHA512 cce39d397a661a5b1c7504f4001e1683231b4d8fb77499102c06532b3ec38f775e544493166e75076460f444b27a15a1ab68237ceb26454b934ee6020c2b0e16
ssdeep 24576:NUPhrrn8YtZM9hjGMjxyK9Ws/6oYJt1wY2ZJIZ7IOAZSRpxtwQDCbzEG:qKjGMjQcGsw7IFSRpxtnDCbF
Entropy 6.704631
Antivirus
AegisLab Trojan.Win32.Alreay.tqBn
Ahnlab HackTool/Win32.Agent
Antiy Trojan[Banker]/Win32.Alreay
Avira TR/AD.Stantinko.ysgqb
BitDefender Trojan.GenericKD.32262757Unclassified
Cyren W32/Alreay.DVWS-3035
ESET a variant of Win32/NukeSped.FQ trojan
Emsisoft Trojan.GenericKD.32262757 (B)
Ikarus Trojan.Win32.HackTool
K7 Trojan ( 00555fff1 )
Kaspersky Trojan-Banker.Win32.Alreay.gen
NANOAV Trojan.Win32.Alreay.fvvzst
Quick Heal Trojan.Alreay
Sophos Troj/ElecFish-A
Symantec Unavailable (production)
VirusBlokAda TrojanBanker.Alreay
Yara Rules
hidden_cobra_consolidated.yara rule electricfish { meta: Author = "CISA trusted 3rd party" Incident = "10135536" Date = "2019-08-14" Category = "Hidden_Cobra" Family = "ELECTRICFISH" Description = "Detects logging functionality" MD5_1 = "0ba6bb2ad05d86207b5303657e3f6874" SHA256_1 = "7cf5d86cc75cd8f0e22e35213a9c051b740bd4667d9879a446f06277782bffd1" strings: $ = "LLgcIP" $ = "CCGC_LOG" $ = "LLGC_LOG" condition: uint16(0) == 0x5a4d and uint16(uint32(0x3c)) == 0x4550 and all of them }
ssdeep Matches

No matches found.

PE Metadata
Compile Date 2018-11-14 20:15:34-05:00
Import Hash 6627b5310efbf9651800ff9ae616be5f
PE Sections
MD5 Name Raw Size Entropy
a781fcd65f93beca71b7b94c3a82ba84 header 1024 2.613318
b081ec452c4927cbc91e8d5d36e75eeb .text 996352 6.592977
131c905ab5153076e77c057bedabcb0d .rdata 340992 6.196190
7261cf1375f63e279189afc08b5486f4 .data 37888 4.740711
bef352ccee242ff585187966059808aa .rsrc 512 5.112624
39f472191c636cf6112a68713b5e6114 .reloc 59392 6.065172
Packers/Compilers/Cryptors
Microsoft Visual C++ ?.?
Description

This file is a malicious Windows 32-bit executable. The application is a command-line utility and its primary purpose is to tunnel traffic between two IP addresses. This file is a variant of 8d9123cd2648020292b5c35edc9ae22e.

Displayed below is the session header of the initial authentication packet, sent to both the source and destination systems:

--Begin TCP session header--
CONNECT Server IP:PORT HTTP/1.0
User-Agent:Mozilla/4.0 (compatible; MSIE 5.5; Win32)
proxy-Connection: Keep-Alive
Pragma: no-cache
Proxy-Authorization: NTLM TlRMTVNTUAABAAAAB4IIAAwADAAoAAAADwAPADQAAAAAAAAAAAAAAFdXVy5HT1RPLkNPTVdJTi00OUFUTlVSNjZNVA==
--End TCP session header--

Recommendations

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".

Contact Information

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://us-cert.gov/forms/feedback/

Document FAQ

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 soc@us-cert.gov.

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

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.us-cert.gov.

Revisions

September 9, 2019: Initial version

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