Armadillov183

Hunt Hypothesis

This detection identifies potential malware activity matching the Armadillov183 signature through YARA scanning on endpoint or file artifacts within the Azure Sentinel environment. Proactive hunting for this specific pattern is essential to uncover early-stage infections that may evade standard heuristic alerts, allowing the SOC team to investigate and contain threats before they escalate into broader incidents.

YARA Rule

rule Armadillov183
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 E0 C1 40 00 68 64 84 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 Armadillov183 detection rule, including tailored filters and exclusions:

• Scenario: Scheduled Antivirus Database Updates

  • Context: The enterprise’s endpoint protection suite (e.g., CrowdStrike Falcon or Microsoft Defender) performs nightly signature updates. During this process, the updater service spawns a temporary executable that matches the Armadillov183 YARA pattern due to shared code libraries or obfuscation techniques similar to the malware family.
  • Filter/Exclusion: Add an exclusion based on the file path and parent process. Exclude any match where Parent_Process_Name is FalconSensor.exe (or MsMpEng.exe) AND File_Path contains \Program Files\CrowdStrike\ or \Windows Defender\.

• Scenario: Automated Software Deployment via SCCM/Intune

  • Context: During a scheduled maintenance window, the Microsoft Endpoint Configuration Manager (SCCM) deploys a new application package to 500+ workstations. The deployment agent (ccmsetup.exe) extracts compressed payloads that contain an installer executable flagged by Armadillov183 as it unpacks and executes the payload in a temporary directory.
  • Filter/Exclusion: Create a rule exclusion for files located in C:\Windows\CCMCache\ or C:\ProgramData\Microsoft\MSCCM\Cache. Additionally, filter out events where the User_Account is a service account (e.g., DOMAIN\SysAdmin-Deploy) rather than an interactive user.

• Scenario: Third-Party Backup Agent Execution

  • Context: The organization uses Veeam Backup & Replication. When the Veeam Transport Service initiates a backup job, it launches a helper process to compress