The aPE Inline Patch ExtraStealth SuperStealth additional

Hunt Hypothesis

This rule detects the presence of the aPE Inline Patch ExtraStealth SuperStealth additional YARA signature, indicating potential use of advanced process injection or stealth mechanisms to hide malicious code execution. Proactively hunting for this low-severity indicator allows the SOC to identify subtle post-exploitation activities that may evade standard behavioral detections, ensuring early visibility into sophisticated adversary tradecraft within Azure Sentinel.

YARA Rule

rule The_aPE_Inline_Patch_ExtraStealth_SuperStealth_additional: PEiD
{
    strings:
        $a = { E8 02 ?? ?? ?? EB 01 C3 3E 8B 44 24 FC 50 B9 ?? ?? ?? ?? E8 ?? ?? ?? ?? 89 }
    condition:
        $a 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 Application Updates via NSIS or Inno Setup Installers

  • Scenario: Many commercial applications (e.g., Adobe Creative Cloud, Oracle Java, or specific vendor management agents) use installers that perform inline patching of existing binaries to update features without full reinstallation. The ExtraStealth and SuperStealth markers in the YARA rule often target specific byte patterns used by these installers to modify code sections in memory or on disk, mimicking stealthy patching behavior.
  • Filter/Exclusion: Exclude processes where the parent process is a known installer executable (e.g., setup.exe, install.exe, unins000.exe) and the target file path resides within standard application installation directories (e.g., C:\Program Files\, C:\Program Files (x86)\). Additionally, exclude if the process command line contains arguments typical of installers (e.g., /S, /silent, /norestart).

• Anti-Malware Self-Healing or Component Updates

  • Scenario: Security suites like CrowdStrike Falcon, Carbon Black, or SentinelOne often employ inline patching mechanisms to update their kernel drivers or user-mode components while running. The “SuperStealth” aspect of the rule may flag the specific hooking or patching techniques used by these EDR agents to maintain persistence and integrity, especially during background update cycles triggered by scheduled tasks.
  • Filter/Exclusion: Exclude processes belonging to known EDR/AV vendor directories (e.g., C:\ProgramData\CrowdStrike\, C:\Program Files\Warp\, C:\Program Files\SentinelOne\). Verify that the process name matches known agent executables (e.g., FalconSensor.exe, cb.exe, sentineloneagent.exe) and that the parent process