PseudoSigner01PackMaster10PEXCloneAnorganix

Hunt Hypothesis

This detection identifies potentially malicious or suspicious executable clones that mimic legitimate signing patterns associated with the PseudoSigner01PackMaster10PEXCloneAnorganix signature, which often indicates early-stage file masquerading by adversaries. Proactively hunting for this behavior in Azure Sentinel is essential to uncover stealthy threats that evade standard signature-based defenses by leveraging low-severity indicators of known cloning techniques before they escalate into active compromises.

YARA Rule

rule PseudoSigner01PackMaster10PEXCloneAnorganix
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 01 01 00 00 E8 83 C4 04 E8 01 90 90 90 E9 5D 81 ED D3 22 40 90 E8 04 02 90 90 E8 EB 08 EB 02 CD 20 FF 24 24 9A 66 BE 47 46 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 }

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

Here are 5 specific false positive scenarios for the PseudoSigner01PackMaster10PEXCloneAnorganix detection rule, including suggested filters and exclusions:

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: During scheduled maintenance windows, System Center Configuration Manager (SCCM) or Microsoft Intune pushes application updates. The deployment engine often extracts packages from a central repository where the PackMaster component is used to stage files before installation. This process involves cloning package structures that match the YARA signature’s “PseudoSigner” and “Anorganix” patterns, triggering alerts on the endpoint even though the activity is expected.
  • Suggested Filter/Exclusion: Create a whitelist based on the parent process name ccmsetup.exe (SCCM) or Microsoft.Intune.ManagementAgent. Additionally, exclude file paths containing \ProgramData\Microsoft\IntuneManagementExtension\Logs\ or \CCM\Service\ from the rule’s scope.

• Scenario: Antivirus Engine Signature Updates

  • Context: Enterprise antivirus solutions like CrowdStrike Falcon or Symantec Endpoint Protection frequently download and install new signature databases. These updates often utilize a packaging mechanism similar to PackMaster to bundle thousands of signatures into a single cloneable unit for distribution. The YARA rule may misinterpret the internal structure of these update packages as a potential cloning artifact associated with the specific detection logic.
  • Suggested Filter/Exclusion: Exclude processes named ccSvcHst.exe (CrowdStrike) or Symantec Antivirus Console. Implement a time-based filter to suppress alerts during known signature update windows (e.g., daily at 02:00 AM UTC).

• Scenario: Backup and Archiving Operations via Veeam

  • Context: Scheduled backup