Armadillov171

Hunt Hypothesis

This rule detects the presence of the Armadillov171 malware family, which is often associated with targeted intrusions and the execution of malicious payloads within the environment. Proactively hunting for this signature allows the SOC team to identify compromised hosts early, potentially before the adversary establishes persistence or begins lateral movement.

YARA Rule

rule Armadillov171
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 [4] 68 [4] 64 A1 }

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

• Scenario: The enterprise deployment of CrowdStrike Falcon or Microsoft Defender for Endpoint agents performs a full disk scan or integrity check, causing the YARA rule to match the agent’s own binary or its associated memory modules during the scanning process.

  • Filter/Exclusion: Exclude processes where the parent image path matches C:\Program Files\CrowdStrike\* or C:\Program Files\Microsoft Defender\*, or filter out detections where the process name is CSAgent.exe or MsMpEng.exe.

• Scenario: A Windows Update service (wuauclt.exe or svchost.exe with the WUA service) downloads and executes a new cumulative update package, temporarily creating a large executable or installer in the C:\Windows\SoftwareDistribution folder that matches the YARA signature due to generic code patterns.

  • Filter/Exclusion: Exclude detections where the file path contains \Windows\SoftwareDistribution\ or where the parent process is wuauclt.exe and the service name is WUA.

• Scenario: An IT administrator runs a PowerShell script to deploy a new internal application or update a configuration file, using Start-Process to launch a temporary installer (e.g., setup.exe from a network share) that resides in a non-standard directory like C:\Temp\Deployments\.

  • Filter/Exclusion: Exclude detections where the process command line contains Start-Process or where the file path starts with C:\Temp\Deployments\ and the user account belongs to the Domain Admins or IT_Ops security group.

• Scenario: A scheduled task for a third-party backup solution (e.g., Veeam or Commvault) initiates a backup