VProtectorV10Build20041213testvcasm

Hunt Hypothesis

This hypothesis targets the execution of VProtector-packed executables, a technique often used by adversaries to obfuscate malware payloads and evade static analysis. Proactively hunting for this specific build in Azure Sentinel allows the SOC to identify potentially compromised endpoints early, as VProtector is frequently associated with information stealers and remote access trojans deployed via phishing or supply chain attacks.

YARA Rule

rule VProtectorV10Build20041213testvcasm
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 55 8B EC 6A FF 68 1A 89 40 00 68 56 89 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

• Legacy .NET Framework Application Deployment: The rule targets the specific VProtect 10 build (20041213) often found in older, un-updated .NET Framework applications or custom internal tools that were packaged using this specific protector version years ago. These binaries may reside in C:\Program Files\InternalTools\ or C:\AppData\Local\... and are executed by service accounts or user profiles.
  • Filter/Exclusion: Exclude files with the path pattern C:\Program Files\InternalTools\ or C:\Program Files (x86)\LegacyApps\ where the executable name matches known legacy application binaries (e.g., LegacyReportGen.exe).
• Scheduled Backup or Maintenance Jobs: A scheduled task (e.g., DailyDBBackup) runs a custom wrapper script or a small C++/C# utility that has been packed with VProtect 10 to reduce size or protect IP. This utility is located in C:\Scripts\Maintenance\ and is triggered by the Task Scheduler service (svchost.exe or taskschd.exe).
  • Filter/Exclusion: Exclude processes where the parent process is taskschd.exe or svchost.exe (specifically the Task Scheduler service) and the file path contains \Scripts\Maintenance\ or \BackupTools\.
• Third-Party Plugin or Add-on for IDEs/Editors: Developers install a specific version of a code formatter, linter, or plugin (e.g., an older build of a C++ code analyzer or a Java decompiler) that uses VProtect 10 for its core binary. These are typically located in user-specific plugin directories like C:\Users\<User>\.vs\extensions\ or C:\Users\<User>\.idea\plugins\. *