VxEddie2000

Hunt Hypothesis

This rule detects the presence of the VxEddie2000 YARA signature, which identifies specific malicious code patterns often associated with targeted intrusions or custom tooling. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to identify compromised endpoints or suspicious artifacts before they can be leveraged for lateral movement or data exfiltration.

YARA Rule

rule VxEddie2000
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 [2] 5E 81 EE [2] FC 2E [4] 2E [4] 4D 5A [2] FA 8B E6 81 C4 [2] FB 3B [5] 50 06 56 1E 8B FE 33 C0 50 8E D8 C5 [3] B4 30 CD 21 }

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 developer or sysadmin executes the vxe (or vxe2) utility from the vxe package (often used for video extraction or specific media processing tasks) on a build server or developer workstation. The binary name or path matches the YARA signature for “VxEddie2000” due to naming conventions or embedded strings.
  • Filter/Exclusion: Exclude processes where the parent process is a known IDE (e.g., code.exe, idea64.exe) or build tool (msbuild.exe, dotnet.exe) and the image path resides in standard development directories (e.g., C:\dev\, C:\projects\, C:\Users\<user>\.nuget\).
• Scenario: An automated scheduled task or CI/CD pipeline job (e.g., Azure DevOps agent, Jenkins slave) runs a script that invokes a custom wrapper script named vxeddie2000.bat or vxeddie2000.ps1 to handle log rotation or data archival, triggering the rule based on the script name or associated binary.
  • Filter/Exclusion: Exclude events where the parent process is a known CI/CD agent (e.g., VstsAgent.exe, jenkins-agent.jar) or a scheduled task service (svchost.exe with Task Scheduler as the parent) and the working directory is within the CI/CD workspace (e.g., C:\agent\, C:\jenkins\workspace\).
• Scenario: A legacy application or internal tool uses a DLL or executable named vxe2000.dll or vxe2000.exe as part of its plugin architecture or media codec support, which is loaded by a trusted host process like chrome.exe or outlook.exe.