SpecialEXEPaswordProtectorV101EngPavolCerven

Hunt Hypothesis

This rule identifies the presence of the Special EXE Password Protector V1.0.1, a tool frequently used by adversaries to obfuscate malicious executables and evade static analysis. Proactively hunting for this indicator in Azure Sentinel allows the SOC to detect potential staging or deployment activities before the protected payload is executed to compromise endpoints.

YARA Rule

rule SpecialEXEPaswordProtectorV101EngPavolCerven
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 00 00 00 00 5D 81 ED 06 00 00 00 89 AD 8C 01 00 00 8B C5 2B 85 FE 75 00 00 89 85 3E }

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: A developer or sysadmin manually runs the SpecialEXEPaswordProtector utility to protect a newly compiled executable for a specific client project or internal tool before deployment.
  • Filter/Exclusion: Exclude processes where the parent process is a known IDE (e.g., devenv.exe, code.exe, idea64.exe) or a build tool (e.g., msbuild.exe, dotnet.exe, java.exe) and the working directory is within a standard source code repository path (e.g., C:\Projects\, D:\Dev\).
• Scenario: A scheduled maintenance job or CI/CD pipeline step automatically applies password protection to application binaries as part of a post-build packaging process.
  • Filter/Exclusion: Exclude executions where the parent process is a task scheduler service (TaskScheduler.exe), a CI agent (e.g., agent.exe for Azure DevOps, jenkins.exe, runner.exe for GitLab), or a shell interpreter (cmd.exe, powershell.exe) initiated by a service account, and the target file path ends in a build output directory (e.g., \bin\, \dist\, \artifacts\).
• Scenario: An IT support technician uses the tool interactively to protect a standalone installer or utility executable before distributing it to end-users via a file share or email.
  • Filter/Exclusion: Exclude executions where the user context is a known service or admin account (e.g., DOMAIN\svc_it, DOMAIN\adm_support) and the process is launched from a standard administrative tools directory (e.g., C:\AdminTools\, C:\Program Files\IT Utilities\) or a shared network drive mapped to an admin share (e.g., \\fileserver\it$\tools\).