VcasmProtector10evcasm

Hunt Hypothesis

This detection identifies the presence of the VCASM Protector 10 EVCASM protection layer, which is frequently utilized by malware to obfuscate executable behavior and evade static analysis. SOC teams should proactively hunt for this indicator in Azure Sentinel to uncover potential stealthy threats that leverage this specific anti-analysis technique to mask malicious activities within their environment.

YARA Rule

rule VcasmProtector10evcasm
{
      meta:
		author="malware-lu"
strings:
		$a0 = { EB 0A 5B 56 50 72 6F 74 65 63 74 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 3-5 specific false positive scenarios for the VcasmProtector10evcasm detection rule, including suggested filters and exclusions:

• Scenario: Automated Backup Agent Execution

  • Context: Enterprise backup solutions like Veeam Backup & Replication or Commvault frequently utilize Vcasm (Virtual Control Application Server Module) components to manage virtual machine snapshots. During scheduled backup windows, these agents spawn processes that match the YARA signature of VcasmProtector10evcasm as they interact with the hypervisor layer.
  • Filter/Exclusion: Create an exclusion based on the parent process name and path. Exclude alerts where ParentProcessName is vbrservice.exe (Veeam) or commvault.exe AND the file path contains \Program Files\Vcasm\.

• Scenario: Patch Management Deployment

  • Context: During major OS patching cycles, tools like Microsoft Endpoint Configuration Manager (SCCM) or Ivanti Neurons often deploy updates to virtualized environments. The deployment agents may invoke the Vcasm protector module to verify integrity before applying patches to guest VMs, triggering the rule during the installation phase.
  • Filter/Exclusion: Implement a time-based filter combined with user context. Exclude events occurring between 01:00 and 05:00 UTC where the LogonUser is a service account (e.g., DOMAIN\SCCM-Service) or the process command line contains keywords like /patch, /deploy, or /install.

• Scenario: Cloud Migration Tool Activity

  • Context: When utilizing migration tools such as Azure Migrate or AWS Application Discovery Service, the agents installed on source servers often invoke Vcasm components to map dependencies and assess application readiness