Armadillov310

Hunt Hypothesis

This detection identifies potential malicious activity associated with the Armadillov310 signature, which may indicate the presence of specific malware or suspicious file artifacts within the environment. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to validate false positives and uncover early-stage threats that might otherwise remain undetected by standard alerting mechanisms.

YARA Rule

rule Armadillov310
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 E0 97 44 00 68 20 C0 42 00 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 83 EC 58 53 56 57 89 65 E8 FF 15 4C 41 44 00 33 D2 8A D4 89 15 90 A1 44 00 8B C8 81 E1 FF 00 00 00 89 0D 8C A1 44 00 C1 E1 08 03 CA 89 0D 88 A1 44 00 C1 E8 10 A3 84 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

Here are 4 specific false positive scenarios for the Armadillov310 detection rule, tailored for an enterprise environment:

• Scenario: Automated Backup Execution by Veeam or Commvault Agents

  • Context: Enterprise backup agents (e.g., Veeam.Backup.Service.exe or commvault.cmd) frequently spawn child processes to compress and encrypt data blocks. The Armadillov310 rule may flag the specific memory signatures of these compression libraries as anomalous behavior typical of the Armadillo malware family.
  • Filter/Exclusion: Exclude process paths containing \Program Files\Veeam\ or \Commvault\ and filter out events where the parent process is a known service account (e.g., NT SERVICE\VeeamBackupService).

• Scenario: Scheduled Code Compilation by Build Servers (Jenkins/GitLab Runner)

  • Context: During nightly CI/CD pipelines, build agents on servers running Docker or Kubernetes nodes execute heavy compilation tasks. The YARA rule might detect the rapid allocation of memory segments and specific string patterns in Java or .NET compilers as matching the Armadillo signature.
  • Filter/Exclusion: Create an exclusion for processes named java.exe, msbuild.exe, or dotnet.exe running under the context of build service accounts (e.g., SYSTEM or Jenkins-Build-User) between 01:00 and 06:00 local time.

• Scenario: Endpoint Protection Scans by CrowdStrike or Microsoft Defender

  • Context: When endpoint protection agents perform deep heuristic scans, they inject code into memory to analyze file structures. This injection mechanism often mimics the “process hollowing” or “memory manipulation” behaviors that Armadillov310 is designed to detect, leading to triggers during full system