Malware Analysis: A Kernel Land Rootkit Loader for FK_Undead

Malware Analysis: A Kernel Land Rootkit Loader for FK_Undead

This article discusses the discovery of a Windows rootkit loader associated with the FK_Undead malware family, which manipulates user proxy settings and intercepts network traffic. The rootkit is disguised as a legitimate Microsoft application and employs various evasion techniques to avoid detection. It is capable of downloading and decrypting payloads from remote servers, leading to severe security risks. Affected: Windows, cybersecurity sector

Keypoints :

  • A Windows rootkit loader has been discovered for the FK_Undead malware family.
  • The rootkit can intercept user network traffic through proxy manipulation.
  • The loader installs itself as a system service, disguised as “Microsoft Foundation Applications.”
  • It stealthily relocates its files to obscure locations to avoid detection.
  • Using the speakeasy emulator, the rootkit’s memory accesses are analyzed for more insights.
  • The rootkit fetches payloads based on the Windows version detected.
  • It employs encryption mechanisms to secure its payloads and deaddrops.
  • Various evasion techniques are used to prevent detection by security solutions.

MITRE Techniques :

  • Persistence (T1547.001) – The rootkit loader registers itself as a system service using the name “EventStore.”
  • Defense Evasion (T1562.001) – The rootkit moves its files and disguises its identity to avoid detection.
  • Command and Control (T1071.001) – It fetches encrypted payloads from remote URLs based on the Windows version.
  • Exfiltration Over Command and Control Channel (T1041) – The malware could potentially exfiltrate data through modified proxy settings.

Indicator of Compromise :

  • [URL] hxxp://tjxgood[.]com:38005/auth.bin
  • [URL] hxxp://tjxupdates[.]com:38005/auth.bin
  • [URL] hxxp://tjxgood[.]com:38005/auth7.bin
  • [URL] hxxp://tjxupdates[.]com:38005/auth7.bin
  • [IP Address] 101.37.76.254

Full Story: https://www.gdatasoftware.com/blog/2024/12/38091-analysis-fk-undead