MSLRHv032afakeASPack211demadicius

Hunt Hypothesis

This detection identifies potential adversary activity involving a specific malicious artifact patterned after fake ASPack variants, as defined by the YARA rule MSLRHv032afakeASPack211demadicius. Although currently flagged with low severity, proactive hunting in Azure Sentinel is essential to uncover early-stage indicators of compromise that may evolve into more critical threats before they trigger higher-severity alerts.

YARA Rule

rule MSLRHv032afakeASPack211demadicius
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 02 00 00 00 EB 09 5D 55 81 ED 39 39 44 00 C3 61 EB 05 E8 EB 04 40 00 EB FA E8 0A 00 00 00 E8 EB 0C 00 00 E8 F6 FF FF FF E8 F2 FF FF FF 83 C4 08 74 04 75 02 EB 02 EB 01 81 50 E8 02 00 00 00 29 5A 58 6B C0 03 E8 02 00 00 00 29 5A 83 C4 04 58 74 04 75 02 EB 02 EB 01 81 0F 31 50 0F 31 E8 0A 00 00 00 E8 EB 0C 00 00 E8 F6 FF FF FF E8 F2 FF FF FF }

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 4 specific false positive scenarios for the detection rule MSLRHv032afakeASPack211demadicius, tailored for a legitimate enterprise environment:

• Scenario: Automated Antivirus Definition Updates

  • Context: The YARA signature likely matches a specific byte pattern or string sequence found in the payload of security definition updates. In an enterprise using Microsoft Defender for Endpoint (or legacy Symantec/Carbon Black), the daily scheduled update job often downloads and unpacks large definition packages that contain this specific artifact structure, triggering the rule even though the file is benign.
  • Suggested Filter: Exclude processes where the parent process name matches MsMpEng.exe (Microsoft Defender) or SymantecDefender.exe, specifically when the file path contains \Updates\ and the event occurs during the configured maintenance window (e.g., 02:00–04:00 UTC).

• Scenario: Enterprise Software Deployment via SCCM/Intune

  • Context: During a mass deployment of application patches or new software installations, tools like Microsoft Endpoint Configuration Manager (SCCM) or Microsoft Intune extract installation packages (.msi/.cab) to the system temp folder. The extraction process creates temporary files that mimic the structural characteristics detected by MSLRHv032afakeASPack211demadicius, causing alerts for every deployed machine.
  • Suggested Filter: Create an exclusion based on the file path prefix %TEMP%\CCM\ or \AppData\Local\Microsoft\IntuneManagementExtension\. Additionally, filter events where the process image name is ccmsetup.exe or IntuneManagementService.exe.

• Scenario: Scheduled Database Backup and Archiving Jobs

  • Context: Legacy backup solutions such as