Armadillov252beta2

Hunt Hypothesis

This rule targets the specific Armadillo v2.52 beta 2 malware variant, a known threat actor tool often used for initial access or lateral movement within enterprise networks. Proactively hunting for this signature allows the SOC to identify compromised hosts early, even if traditional behavioral detections have not yet triggered, thereby reducing the dwell time of this low-severity but persistent threat in the Azure environment.

YARA Rule

rule Armadillov252beta2
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 [4] B0 [4] 68 60 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 83 EC 58 53 56 57 89 65 E8 FF [3] 15 24 }

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: Execution of the armadillo CLI tool (version 2.5.2-beta2) by a DevOps engineer during a local build pipeline or CI/CD job that includes a custom packaging step. The binary name or version string matches the YARA pattern, but the process is spawned by a known build agent (e.g., jenkins-agent.exe or github-actions-runner.exe).

  • Filter/Exclusion: Exclude if the parent process name is in the list ["jenkins-agent.exe", "github-actions-runner.exe", "azure-devops-agent.exe"] AND the file path contains /build/ or /ci/.

• Scenario: A security team performing a controlled test of the Armadillo framework in a dedicated lab VM or containerized environment (e.g., Docker or Kubernetes pod) where the binary is mounted or copied to a temporary directory for validation. The process runs under a service account or non-interactive user with a specific UID/GID.

  • Filter/Exclusion: Exclude if the process is running inside a container (detected via container_id or is_container field) OR if the user account name matches sec-test-* or lab-user-*.

• Scenario: An automated scheduled task (e.g., Windows Task Scheduler or cron job) that runs a custom script to archive or compress logs using a tool named armadillov252beta2 as a wrapper or alias for a standard compression utility (e.g., 7z or tar). The task runs under the SYSTEM or LocalService account at a fixed interval.

  • Filter/Exclusion: Exclude if the parent process is svchost.exe (for Windows Task Scheduler) or cron/crond (for Linux), AND the command line contains keywords like `