XJXPALLiNSoN

Hunt Hypothesis

This YARA rule targets specific memory or file patterns associated with the XJXPALLiNSoN signature, likely indicating the presence of a low-severity malware variant or suspicious code injection. Proactively hunting for this signature allows the SOC team to identify dormant or stealthy threats that may evade standard behavioral detections, ensuring early containment within the Azure Sentinel environment.

YARA Rule

rule XJXPALLiNSoN
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 [2] 40 00 68 [2] 40 00 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 83 EC 44 53 56 57 66 9C }

condition:
		$a0 at pe.entry_point
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: A DevOps engineer runs a custom Python script using the pyinstaller tool to bundle a CI/CD pipeline utility into a single executable for deployment to Windows agents. The resulting binary contains embedded Python bytecode and standard library references that match the XJXPALLiNSoN signature due to its generic structure.

  • Filter/Exclusion: Exclude files located in specific build artifact directories (e.g., C:\Builds\artifacts\) or filter by parent process python.exe or pyinstaller.exe if the YARA rule targets the interpreter or build tool itself.

• Scenario: An IT administrator installs a new version of the 7-Zip file archiver or updates the WinRAR client. The installer or the main executable (7zFM.exe or WinRAR.exe) may contain specific string patterns or section headers that trigger the XJXPALLiNSoN rule, especially if the rule is designed to catch packed or obfuscated binaries.

  • Filter/Exclusion: Whitelist known trusted executables by hash or path (e.g., C:\Program Files\7-Zip\7zFM.exe) and exclude processes spawned by msiexec.exe or setup.exe during installation windows.

• Scenario: A security team performs a monthly vulnerability scan using Nessus or Qualys agents. The agent’s update mechanism downloads new plugin packs or signature databases, which are often compressed or packed archives. If the XJXPALLiNSoN rule inspects memory or disk files, it may flag the temporary unpacked signature files or the agent’s helper executables.

  • Filter/Exclusion: Exclude files in temporary directories used by the scanner (e.g., C:\ProgramData\Tenable\Nessus\ or `C:\