Armadillov260

Hunt Hypothesis

This detection identifies the execution of files matching the Armadillov260 signature, which may indicate the presence of a specific malware variant or legitimate software component within the environment. SOC teams should proactively hunt for this indicator in Azure Sentinel to validate its behavior against known baselines and prevent potential low-severity threats from evolving into significant incidents.

YARA Rule

rule Armadillov260
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 D0 [3] 68 34 [3] 64 A1 [4] 50 64 89 25 [4] 83 EC 58 53 56 57 89 65 E8 FF 15 68 [3] 33 D2 8A D4 89 15 84 }

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 Armadillov260 detection rule, tailored for a legitimate enterprise environment:

• Scenario: Automated Backup Execution by Veeam Backup & Replication

  • Context: The nightly backup job initiates a large data transfer process where the Veeam.Backup.Service.exe process spawns multiple child processes to handle chunking and encryption, mimicking the behavior of Armadillo’s modular architecture.
  • Filter/Exclusion: Exclude the specific service executable path: C:\Program Files\Veeam\Backup and Replication Enterprise Edition 12\Backup Service\BackupService.exe from triggering this rule during the defined maintenance window (e.g., 01:00–05:00 UTC).

• Scenario: Microsoft Defender Antivirus Real-Time Scanning

  • Context: During peak business hours, the MsMpEng.exe process performs deep heuristic scans on user directories. The rule detects the scanning engine’s dynamic loading of signature modules as a potential Armadillo variant due to similar memory footprint and API call sequences.
  • Filter/Exclusion: Create an exclusion for the parent process MsMpEng.exe located at C:\Program Files\Windows Defender\MsMpEng.exe, specifically filtering out events where the file hash matches known Microsoft-signed binaries in the “Real-Time Protection” category.

• Scenario: Scheduled Group Policy Update Deployment

  • Context: The System Center Configuration Manager (SCCM) agent (ccmexec.exe) pushes a new policy update to endpoints, triggering a background script that modifies registry keys and injects DLLs into system processes, which the YARA rule interprets as Armadillo’s initialization sequence.
  • Filter/Exclusion: Exclude events originating from `C:\Windows\CCM\CcmExec.exe