AnticrackSoftwareProtectorv109ACProtect

Hunt Hypothesis

This rule identifies the presence of ACProtect, a commercial software protection tool often used by adversaries to obfuscate malicious payloads and evade static analysis. Proactively hunting for this signature allows the SOC to detect potentially hidden or packed executables that may be leveraging commercial protection mechanisms to mask their true intent within the environment.

YARA Rule

rule AnticrackSoftwareProtectorv109ACProtect
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 [8] 00 00 [12] E8 01 00 00 00 ?? 83 04 24 06 C3 [5] 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

• Scenario: Execution of the ACProtect.exe or ACProtect64.exe utility by a DevOps engineer or application support team to apply or verify code protection (obfuscation/anti-debugging) on a newly built .NET or C++ application binary before deployment to a staging environment.
  • Filter/Exclusion: Exclude processes where the parent process is a build tool (e.g., msbuild.exe, dotnet.exe, cmd.exe invoked by CI/CD agents) or where the command line contains arguments like /p, /a, or /v (common ACProtect flags for protect, analyze, or verbose).
• Scenario: A scheduled maintenance job (e.g., via Task Scheduler or Cron) that runs a custom script to re-protect critical proprietary libraries or executables after a patching cycle, using the ACProtect command-line interface to ensure consistency in the binary’s protection layer.
  • Filter/Exclusion: Exclude executions originating from known service accounts (e.g., svc_build, svc_deploy) or paths under standard build artifacts directories (e.g., C:\Builds\, D:\Artifacts\) where the process name matches ACProtect* and the working directory is not a user profile.
• Scenario: An IT administrator manually testing the integrity of a protected executable on a jump host or build server to verify that the anti-crack protections are still active after a recent update, running the tool from a temporary directory or the tool’s installation folder.
  • Filter/Exclusion: Exclude processes where the image path contains keywords like Tools, Utilities, Bin, or ACProtect in the directory name, and the parent process is an interactive shell (cmd.exe, powershell.exe, pwsh.exe) rather than a service or system process.
• Scenario: