VProtector10Xvcasm

Hunt Hypothesis

This detection identifies potential malicious activity associated with the VProtector10Xvcasm signature, which may indicate the presence of specific malware or unauthorized virtualization components within the environment. Proactively hunting for this indicator in Azure Sentinel allows the SOC team to validate its legitimacy early and prevent low-severity signals from escalating into broader security incidents before they impact critical workloads.

YARA Rule

rule VProtector10Xvcasm
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 [4] 68 [4] 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 C3 FF 35 E8 03 00 00 00 C7 84 00 58 EB 01 E9 83 C0 07 50 C3 FF 35 E8 07 00 00 00 C7 83 83 C0 13 EB 0B 58 EB 02 CD 20 83 C0 02 EB 01 E9 50 C3 E8 B9 04 00 00 00 E8 1F 00 00 00 EB FA E8 16 00 00 00 E9 EB F8 00 00 58 EB 09 0F 25 E8 F2 FF FF FF 0F B9 49 75 F1 EB 05 EB F9 EB F0 D6 EB 01 0F 31 F0 EB 0C 33 C8 EB 03 EB 09 0F 59 74 05 75 F8 51 EB F1 E8 16 00 00 00 8B 5C 24 0C 8B A3 C4 00 00 00 64 8F 05 00 00 00 00 83 C4 04 EB 14 64 FF 35 00 00 00 00 64 89 25 00 00 00 00 33 C9 99 F7 F1 E9 E8 05 00 00 }

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 VProtector10Xvcasm detection rule, along with recommended filters and exclusions:

• Scenario: Scheduled Antivirus Engine Updates

  • Context: The VProtector engine (often part of a broader suite like Trend Micro or similar) performs nightly signature database updates. During this process, the VProtector10Xvcasm service spawns child processes to download and install new definitions, which mimics the behavior of a new security agent installation or a suspicious binary execution often flagged by YARA rules targeting virtualization components.
  • Filter/Exclusion: Create an exclusion rule for the specific process path C:\Program Files\VProtector\vcasm.exe (or equivalent) when executed by the system account (NT AUTHORITY\SYSTEM) between 02:00 and 04:00 daily. Alternatively, filter out alerts where the parent process is wuauserv.exe or the specific update service associated with VProtector.

• Scenario: Enterprise Backup Agent Scanning

  • Context: Enterprise backup solutions like Veeam Backup & Replication or Rubrik utilize virtualization APIs to scan guest OS volumes. When these agents interact with the host’s hypervisor layer, they may trigger the vcasm (Virtual Cloud Application Service Manager) component to validate disk states, generating a signature that matches the VProtector detection logic for potential unauthorized virtual machine management tools.
  • Filter/Exclusion: Exclude alerts where the parent process is vbrservice.exe (Veeam) or rubrik-agent.exe. Additionally, add a filter to suppress detections if the command line arguments contain keywords like --scan, --backup, or specific job IDs associated with known backup schedules.

• **Scenario: Patch Management Deployment via SCCM