Armadillov160a

Hunt Hypothesis

This detection identifies the presence of the Armadillov160a malware signature within endpoint logs, indicating potential file-based execution or persistence attempts by an adversary. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to validate low-severity alerts against broader threat intelligence and prevent silent lateral movement before it escalates into a critical incident.

YARA Rule

rule Armadillov160a
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 98 71 40 00 68 48 2D 40 00 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 83 EC 58 }

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 Armadillov160a detection rule, along with targeted filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The enterprise uses Microsoft Defender Antivirus (or Symantec Endpoint Protection) which runs a scheduled daily update job at 2:00 AM. During this window, the update service (MpCmdRun.exe or SymantecEngine.exe) extracts new definition packages that match the specific YARA signature patterns of Armadillov160a due to similar PE header structures or embedded script logic.
  • Filter/Exclusion: Create a rule exclusion based on the Process Name (MpCmdRun.exe, SymantecEngine.exe) and restrict the detection scope to exclude events occurring between 02:00 and 04:00 UTC. Alternatively, add these specific executable paths to the YARA rule’s exclude list.

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: The IT team utilizes Microsoft Configuration Manager (SCCM) or Microsoft Intune to push cumulative Windows updates during business hours. The deployment agent (WUAHandler.exe or CcmExec.exe) extracts and installs patches that contain compressed archives with signatures mimicking the Armadillov160a heuristic, triggering alerts on the client machines.
  • Filter/Exclusion: Implement a filter to exclude processes running under the “System” user account where the parent process is CcmExec.exe. Additionally, add a specific path exclusion for the software distribution point directory (e.g., \\<SCCMServer>\SoftwareDistribution\Content).

• Scenario: Backup Agent Data Indexing

  • Context: The organization employs **Veeam Backup &