VxEddie1800

Hunt Hypothesis

This detection identifies potential malicious activity associated with the VxEddie1800 signature, which may indicate early-stage file-based threats or specific malware variants within the environment. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to validate low-severity alerts and uncover hidden persistence mechanisms before they escalate into significant incidents.

YARA Rule

rule VxEddie1800
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 [2] 5E 81 EE [2] FC 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 C4 [3] 2E [4] 2E }

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 VxEddie1800 detection rule, tailored for a legitimate enterprise environment:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The YARA rule triggers when the endpoint protection agent (e.g., Microsoft Defender or CrowdStrike) downloads and installs new signature definitions during off-hours. The update process often involves unpacking compressed archives containing executable payloads that match the VxEddie1800 pattern.
  • Filter/Exclusion: Create a filter to exclude processes where the ImageName matches *DefenderService.exe or *CrowdStrike.exe AND the ParentProcessName is svchost.exe. Additionally, restrict this exclusion to run only between 02:00 and 06:00 local time.

• Scenario: Enterprise Software Deployment via SCCM/Intune

  • Context: During a mass deployment of a new application (e.g., Adobe Acrobat or Zoom), the System Center Configuration Manager (SCCM) agent extracts installation packages on the client machine. The extraction utility creates temporary executable files in the %TEMP% directory that mimic the behavior detected by VxEddie1800.
  • Filter/Exclusion: Exclude alerts where the CommandLine contains known deployment tool identifiers such as ccmsetup.exe, intunewinagent.exe, or msiexec /package. Ensure the file path is located within standard enterprise directories like C:\Windows\CCM\Cache or C:\ProgramData\Microsoft\IntuneManagementExtension.

• Scenario: Automated Backup and Archiving Jobs

  • Context: Enterprise backup solutions (e.g., Veeam Agent or Rubrik) periodically compress large datasets into .zip or .7z archives. The archiver executable often spawns child processes