Armadillov177

Hunt Hypothesis

This rule detects the presence of the Armadillov177 YARA signature, which typically indicates the execution of a specific low-severity malware strain or script often used for initial access or payload delivery. Proactively hunting for this indicator allows the SOC team to identify compromised hosts in Azure Sentinel before the adversary can establish persistence or escalate privileges, thereby reducing the dwell time of potential threats.

YARA Rule

rule Armadillov177
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 B0 71 40 00 68 6C 37 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

• Scenario: A DevOps engineer runs a custom PowerShell script to deploy a new microservice, which includes a base64-encoded configuration blob or a compressed payload (e.g., using Compress-Archive or Expand-Archive) that matches the byte pattern of Armadillov177.
  • Filter/Exclusion: Exclude processes where the parent process is powershell.exe or pwsh.exe and the command line contains specific deployment keywords like deploy, release, or k8s. Additionally, whitelist specific script paths under C:\Scripts\Deploy\.
• Scenario: An IT administrator performs a routine backup of a SQL database using sqlcmd or a custom backup utility that writes a temporary compressed file to the %TEMP% directory, which inadvertently matches the YARA signature due to the file’s header or structure.
  • Filter/Exclusion: Exclude files located in standard temporary directories (%TEMP%, %TMP%) if the parent process is a known backup tool such as VeeamBackup.exe, CommvaultAgent.exe, or sqlbackup.exe.
• Scenario: A security team runs a YARA scan against a known-good application binary (e.g., chrome.exe or outlook.exe) to verify integrity, and the file is temporarily copied to a staging area where it matches the rule due to a specific code section or resource block.
  • Filter/Exclusion: Exclude processes where the parent process is yara.exe or yara64.exe. Also, whitelist specific staging directories like C:\SecurityTools\Staging\ for files that are less than 24 hours old.
• Scenario: A Java or .NET application (e.g., a custom internal ERP system) loads a native library or resource file (.dll or `.