AHPack V01 FEUERRADER

Hunt Hypothesis

This rule detects the presence of the AHPack V01 FEUERRADER YARA signature, which identifies specific malicious code patterns often associated with targeted intrusion sets or custom tooling. Proactively hunting for this signature allows the SOC team to uncover dormant or low-fidelity implants that may have evaded standard behavioral detections, ensuring early identification of persistent threats within the Azure Sentinel environment.

YARA Rule

rule AHPack_V01_FEUERRADER: PEiD
{
    strings:
        $a = { 60 68 54 ?? ?? 00 B8 48 ?? ?? 00 FF 10 68 B3 ?? ?? 00 50 B8 44 ?? ?? 00 FF 10 68 00 }
    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

• Legacy Application Deployment via Group Policy: When deploying older, unmanaged Windows applications (e.g., specific versions of Adobe Reader, Java, or legacy ERP clients) via Group Policy Software Installation, the installer often uses generic or obfuscated PE headers that may match the AHPack signature.

  • Filter/Exclusion: Exclude files located in C:\Windows\Installer\ or C:\Program Files (x86)\ where the parent process is gpupdate.exe or svchost.exe (specifically the appmgmt service), and limit the exclusion to known legacy application paths.

• Driver Installation for Specialized Hardware: Installing drivers for specialized enterprise hardware (e.g., Zebra barcode scanners, HP plotter drivers, or specific RAID controller updates) often involves custom installers that pack their executables to reduce size or protect IP. These installers may reside in temporary directories (%TEMP% or %LOCALAPPDATA%) and trigger the YARA rule.

  • Filter/Exclusion: Exclude files in %TEMP% or %LOCALAPPDATA%\Temp if the parent process is setup.exe, install.exe, or a known vendor-specific installer (e.g., ZebraSetup.exe, HPDriverInstall.exe), and verify the file hash against a known-good baseline for those specific drivers.

• Scheduled Maintenance Jobs for Third-Party Backup/AV Tools: Some enterprise backup solutions (e.g., Veeam, Commvault) or anti-malware tools (e.g., CrowdStrike Falcon, Carbon Black) may drop temporary agent binaries or update packages into system directories or user profiles during scheduled maintenance windows. These binaries might be packed or signed with a generic certificate that matches the AHPack heuristic.

  • Filter/Exclusion: Exclude files in C:\ProgramData\ or