PrivatePersonalPackerPPP102ConquestOfTroycom

Hunt Hypothesis

This hunt hypothesis targets adversaries utilizing the Conquest of Troy packer to obfuscate malicious payloads within private personal executables, a technique often employed to evade signature-based detection and conceal command-and-control communications. The SOC team should proactively hunt for this behavior in Azure Sentinel because identifying these packed binaries early allows analysts to isolate potentially compromised assets before they establish persistence or exfiltrate sensitive data through encrypted channels.

YARA Rule

rule PrivatePersonalPackerPPP102ConquestOfTroycom
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 17 00 00 00 E8 68 00 00 00 FF 35 2C 37 00 10 E8 ED 01 00 00 6A 00 E8 2E 04 00 00 E8 41 04 00 00 A3 74 37 00 10 6A 64 E8 5F 04 00 00 E8 30 04 00 00 A3 78 37 00 10 6A 64 E8 4E 04 00 00 E8 1F 04 00 00 A3 7C 37 00 10 A1 74 37 00 10 8B 1D 78 37 00 10 2B D8 8B 0D 7C 37 00 10 2B C8 83 FB 64 73 0F 81 F9 C8 00 00 00 73 07 6A 00 E8 D9 03 00 00 C3 6A 0A 6A 07 6A 00 E8 D3 03 00 00 A3 20 37 00 10 50 6A 00 E8 DE 03 00 00 A3 24 37 00 10 FF 35 20 37 00 10 6A 00 E8 EA 03 00 00 A3 30 37 00 10 FF 35 24 37 00 10 E8 C2 03 00 00 A3 28 37 00 10 8B 0D 30 37 00 10 8B 3D 28 37 00 10 EB 09 49 C0 04 39 55 80 34 39 24 0B C9 }

condition:
		$a0
}

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 4 specific false positive scenarios for the PrivatePersonalPackerPPP102ConquestOfTroycom detection rule, including suggested filters and exclusions:

• Scenario: Deployment of Microsoft Office Updates via SCCM/Intune

  • Context: The YARA rule detects the PrivatePersonalPacker signature often used in compressed installer bundles. When System Center Configuration Manager (SCCM) or Microsoft Intune deploys cumulative updates for Microsoft 365 Apps, it frequently extracts a .exe wrapper that matches this specific packer hash before executing the actual update logic.
  • Suggested Filter/Exclusion: Create an exclusion based on the Parent Process Name (ccmsetup.exe, msiexec.exe, or IntuneManagementExtension.exe) and restrict the match to file paths containing \Microsoft Office\ or \Program Files\Common Files\.

• Scenario: Execution of Antivirus Definition Updates (e.g., CrowdStrike or SentinelOne)

  • Context: Endpoint Detection and Response (EDR) agents often download and unpack definition updates using a proprietary packer that mimics the PrivatePersonalPacker structure. Specifically, CrowdStrike’s Falcon Sensor or SentinelOne’s Singularity Agent may trigger this rule when their background update service (FalconService.exe or SentinelAgent.exe) extracts new signature databases.
  • Suggested Filter/Exclusion: Exclude processes where the Image Path contains \CrowdStrike\ or \SentinelOne\, and filter by specific known SHA-256 hashes of the legitimate update executables to prevent re-triggering on every daily scan cycle.

• Scenario: Scheduled Backup Jobs Using Veeam or Acronis

  • Context: Enterprise backup solutions often utilize a custom packing engine for incremental data blocks. When a scheduled