GoatsMutilatorV16Goat e0f

Hunt Hypothesis

This detection identifies potential malware activity matching the specific signature of the GoatsMutilator variant, which may indicate an early-stage compromise or lateral movement attempt within the environment. Proactive hunting for this indicator in Azure Sentinel is essential to validate false positives and uncover hidden persistence mechanisms before they escalate into a significant security incident.

YARA Rule

rule GoatsMutilatorV16Goat_e0f
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 EA 0B 00 00 [3] 8B 1C 79 F6 63 D8 8D 22 B0 BF F6 49 08 C3 02 BD 3B 6C 29 46 13 28 5D }

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 GoatsMutilatorV16Goat e0f detection rule, including suggested filters and exclusions:

• Scenario: Automated Backup Execution by Veeam

  • Context: The nightly backup job executed by Veeam Agent or Veeam Enterprise Manager creates temporary executable processes in the system temp directory to handle data compression. These processes often utilize memory patterns and file signatures that overlap with the YARA rule’s logic for Goat e0f, triggering a match on legitimate backup artifacts.
  • Suggested Filter/Exclusion: Add an exclusion based on the parent process name VeeamAgent.exe or vbrservice.exe. Alternatively, configure the detection to ignore alerts where the file path contains \Program Files\Veeam\ or \Temp\VeeamBackup\.

• Scenario: Microsoft Defender Antivirus Real-Time Scan

  • Context: When Microsoft Defender performs real-time scanning on large document repositories (e.g., OneDrive for Business sync folders), it spawns MsMpEng.exe child processes that load specific signature modules. The YARA rule may misinterpret the memory footprint of these signature modules as the Goat e0f payload, particularly when scanning files with similar header structures.
  • Suggested Filter/Exclusion: Create a whitelist entry for the process image path C:\Program Files\Windows Defender\MsMpEng.exe. Additionally, exclude alerts where the user context is NT SERVICE\WdNisSvc (Windows Defender Network Inspection Service).

• Scenario: Scheduled PowerShell Script Deployment

  • Context: A scheduled Task running a custom PowerShell script (powershell.exe) to deploy configuration updates or patch management via SCCM/Intune. The script invokes a compiled .NET assembly that mimics the behavioral characteristics of the Goat