Armadillov200

Hunt Hypothesis

This detection identifies potential file-based threats matching the Armadillov200 signature, which may indicate early-stage malware activity or suspicious artifact presence within the environment. Proactively hunting for this rule in Azure Sentinel allows the SOC team to validate low-severity alerts before they escalate, ensuring comprehensive coverage of known threat patterns that might otherwise be overlooked during routine monitoring.

YARA Rule

rule Armadillov200
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 00 02 41 00 68 C4 A0 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 Armadillov200 detection rule, including tailored filters and exclusions:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The endpoint protection suite (e.g., Microsoft Defender or CrowdStrike) performs a nightly scheduled update of virus definition signatures. This process often involves the extraction of compressed archives containing new heuristic rules, which mimics the behavior patterns Armadillov200 is designed to catch.
  • Filter/Exclusion: Create an exclusion based on the specific service account used by the AV engine (e.g., NT SERVICE\DefenderSvc) and exclude file paths within the vendor’s update directory, such as C:\ProgramData\Microsoft\Windows Defender\Platform.

• Scenario: Enterprise Backup Agent Operations

  • Context: The enterprise backup solution (e.g., Veeam or Commvault) runs a scheduled job to compress and archive log files or database snapshots. The compression engine creates temporary executable wrappers during the packaging phase, triggering the YARA rule’s signature for potential obfuscation techniques.
  • Filter/Exclusion: Exclude processes spawned by the backup agent service (e.g., Veeam.Backup.Service.exe or commvault.cmd) and filter out events where the parent process is a known backup scheduler running during defined maintenance windows (e.g., 02:00–04:00 UTC).

• Scenario: IT Asset Management Software Deployment

  • Context: The IT department uses an asset management tool like Ivanti or SCCM to deploy software patches. During the deployment, the agent extracts installation packages (MSI/EXE) from a local cache folder before execution, generating file artifacts that match the Armadillov200 signature for staged executables.
  • **Filter/