VProtectorV10Avcasm

Hunt Hypothesis

This detection identifies the presence of the VProtector antivirus engine (version 10) on endpoints, signaling potential legacy security software that may lack coverage against modern threats or exhibit performance overhead. A proactive hunt is recommended to assess whether these agents are fully patched and effectively integrated with Azure Sentinel’s data ingestion pipelines to ensure comprehensive visibility across the environment.

YARA Rule

rule VProtectorV10Avcasm
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 8A 8E 40 00 68 C6 8E 40 00 64 A1 00 00 00 00 50 64 89 25 00 00 00 00 E8 03 00 00 00 C7 84 00 58 EB 01 E9 83 C0 07 50 }

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 VProtectorV10Avcasm detection rule, including suggested filters and exclusions:

• Scenario: Automated Antivirus Scanning by Veeam Backup & Replication

  • Context: The VProtector service (part of Veeam) frequently spawns child processes to scan backup repositories or perform integrity checks on virtual machines. These scans often trigger the AVCASM signature when accessing specific VM configuration files (.vmdk, .vmx).
  • Suggested Filter/Exclusion: Add a process exclusion for Veeam.Backup.Service.exe and its child processes (Veeam.Backup.Avcasm.exe) on hosts running Veeam. Alternatively, create a filter to exclude alerts where the parent process is svchost.exe (specifically the VeeamBackupService service) accessing paths within the backup repository directory (e.g., C:\Veeam\BackupRepository\).

• Scenario: Scheduled PowerShell Script Execution for Configuration Management

  • Context: Enterprise IT teams often run scheduled PowerShell jobs using tools like Ansible, Chef, or custom scripts to update AV policies. These scripts may invoke the VProtector engine directly to push configuration changes, triggering the rule when they instantiate temporary ASM (Active Service Module) components.
  • Suggested Filter/Exclusion: Implement a filter that excludes alerts originating from powershell.exe where the command line contains keywords like “VProtector” or “AVCASM”. Additionally, exclude specific scheduled task names such as \Microsoft\Veeam\Backup\PolicyUpdate if they are known to trigger this behavior.

• Scenario: Third-Party Endpoint Detection and Response (EDR) Integration

  • Context: When an EDR solution like **