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SombRAT

SombRAT is a modular backdoor written in C++ that has been in use since at least 2019. SombRAT has been used to download and execute malicious payloads, including FIVEHANDS ransomware.[1][2][3]

ID: S0615
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Type: MALWARE
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Platforms: Windows
Version: 1.0
Created: 26 May 2021
Last Modified: 15 October 2021
Enterprise Layer
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Techniques Used

Domain ID Name Use
Enterprise T1071 .004 Application Layer Protocol: DNS

SombRAT can communicate over DNS with the C2 server.[1][2]
Enterprise T1005 Data from Local System

SombRAT has collected data and files from a compromised host.[1][3]
Enterprise T1074 .001 Data Staged: Local Data Staging

SombRAT can store harvested data in a custom database under the %TEMP% directory.[1]
Enterprise T1140 Deobfuscate/Decode Files or Information

SombRAT can run upload to decrypt and upload files from storage.[1][3]
Enterprise T1568 .002 Dynamic Resolution: Domain Generation Algorithms

SombRAT can use a custom DGA to generate a subdomain for C2.[1]
Enterprise T1573 .002 Encrypted Channel: Asymmetric Cryptography

SombRAT can SSL encrypt C2 traffic.[1][2][3]
Enterprise T1083 File and Directory Discovery

SombRAT can execute enum to enumerate files in storage on a compromised system.[1]
Enterprise T1070 .004 Indicator Removal on Host: File Deletion

SombRAT has the ability to run cancel or closeanddeletestorage to remove all files from storage and delete the storage temp file on a compromised host.[1]
Enterprise T1105 Ingress Tool Transfer

SombRAT has the ability to download and execute additional payloads.[1][2][3]
Enterprise T1036 Masquerading

SombRAT can use a legitimate process name to hide itself.[3]
Enterprise T1106 Native API

SombRAT has the ability to respawn itself using ShellExecuteW and CreateProcessW.[1]
Enterprise T1095 Non-Application Layer Protocol

SombRAT has the ability to use TCP sockets to send data and ICMP to ping the C2 server.[1][2]
Enterprise T1027 Obfuscated Files or Information

SombRAT can encrypt strings with XOR-based routines and use a custom AES storage format for plugins, configuration, C2 domains, and harvested data.[1][2][3]
Enterprise T1057 Process Discovery

SombRAT can use the getprocesslist command to enumerate processes on a compromised host.[1][2][3]
Enterprise T1055 .001 Process Injection: Dynamic-link Library Injection

SombRAT can execute loadfromfile, loadfromstorage, and loadfrommem to inject a DLL from disk, storage, or memory respectively.[1]
Enterprise T1090 Proxy

SombRAT has the ability to use an embedded SOCKS proxy in C2 communications.[3]
Enterprise T1082 System Information Discovery

SombRAT can execute getinfo to enumerate the computer name and OS version of a compromised system.[1]
Enterprise T1033 System Owner/User Discovery

SombRAT can execute getinfo to identify the username on a compromised host.[1][3]
Enterprise T1007 System Service Discovery

SombRAT can enumerate services on a victim machine.[1]
Enterprise T1124 System Time Discovery

SombRAT can execute getinfo to discover the current time on a compromised host.[1][3]

Groups That Use This Software

ID Name References
G0132 CostaRicto

[1]

References

  1. The BlackBerry Research and Intelligence Team. (2020, November 12). The CostaRicto Campaign: Cyber-Espionage Outsourced. Retrieved May 24, 2021.
  2. McLellan, T. and Moore, J. et al. (2021, April 29). UNC2447 SOMBRAT and FIVEHANDS Ransomware: A Sophisticated Financial Threat. Retrieved June 2, 2021.
  1. CISA. (2021, May 6). Analysis Report (AR21-126A) FiveHands Ransomware. Retrieved June 7, 2021.