ExeShieldv29

Hunt Hypothesis

This rule detects the presence of ExeShield, a commercial executable protection tool often used by adversaries to obfuscate malware binaries and evade static analysis. Proactively hunting for this indicator in Azure Sentinel helps identify potential low-severity threats or legitimate software that may be leveraging executable packing to hide malicious payloads within the environment.

YARA Rule

rule ExeShieldv29
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 00 00 00 00 5D 81 ED 0B 20 40 00 B9 EB 08 00 00 8D BD 53 20 40 00 8B F7 AC [3] F8 }

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

• Legitimate Software Updates via MSI/EXE Installers: Enterprise patch management tools (e.g., SCCM, PDQ Deploy) often execute temporary EXE files in the C:\Windows\Temp or user profile directories to install updates for applications like Adobe Creative Cloud, Java, or .NET Framework. These installers may contain specific byte patterns or version strings that match the ExeShieldv29 signature.

  • Filter/Exclusion: Exclude processes where the parent process is a known deployment agent (e.g., CcmExec.exe, PDQDeploy.exe, Wuaexhost.exe) or where the file path contains \Temp\ and the file extension is .exe with a recent creation time (< 1 hour).

• Antivirus/EDR Self-Update Binaries: Security suites like CrowdStrike Falcon, SentinelOne, or Carbon Black frequently download and execute update binaries in isolated directories (e.g., C:\ProgramData\CrowdStrike\ or C:\Program Files\SentinelOne\) to update their detection engines or agents. These binaries are often signed but may contain specific version headers or obfuscated strings that trigger the YARA rule.

  • Filter/Exclusion: Exclude files located in standard EDR vendor directories (e.g., C:\ProgramData\CrowdStrike\, C:\Program Files\SentinelOne\, C:\Program Files\Kaspersky\) and verify the digital signature is valid and issued by the respective vendor.

• Developer Build Artifacts in CI/CD Pipelines: In development environments, tools like Jenkins, GitLab CI, or Azure DevOps Agents execute build scripts and temporary executables in workspace directories (e.g., C:\jenkins\workspace\, C:\gitlab-runner\builds\). These temporary EXEs are often unob