AHTeamEPProtector03fakeZCode101FEUERRADER

Hunt Hypothesis

This hunt hypothesis detects potential endpoint protection evasion or false positive scenarios where a specific YARA signature identifies anomalous code execution patterns that may indicate stealthy adversary activity. A SOC team should proactively investigate these signals in Azure Sentinel to distinguish between benign operational noise and early-stage threats attempting to bypass standard security controls through subtle behavioral deviations.

YARA Rule

rule AHTeamEPProtector03fakeZCode101FEUERRADER
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 90 [46] 90 FF E0 E9 12 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 E9 FB FF FF FF C3 68 00 00 00 00 64 FF 35 }

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

Here are 4 specific false positive scenarios for the detection rule AHTeamEPProtector03fakeZCode101FEUERRADER, along with recommended filters and exclusions:

• Scenario: Scheduled Antivirus Database Updates

  • Context: The enterprise endpoint protection agent (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) triggers a background scan or signature update job during off-hours. This process often spawns temporary worker threads that mimic the behavior of the “fake ZCode” pattern defined in the YARA rule.
  • Filter/Exclusion: Create an exclusion based on the specific process name and path of the AV engine’s updater service (e.g., C:\Program Files\CrowdStrike\csfalcon.exe or MsMpEng.exe) running under the system account. Add a time-based filter to exclude alerts generated between 02:00 and 05:00 local time for these specific processes.

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: During a scheduled Windows Update or application patch deployment, the System Center Configuration Manager (SCCM) or Microsoft Intune agent extracts compressed payloads to the %TEMP% directory. The extraction utility often generates file hashes and execution patterns that match the “FEUERRADER” signature logic of the rule.
  • Filter/Exclusion: Exclude alerts where the parent process is ccmsetup.exe, IntuneManagementExtension.exe, or wuauserv.exe. Additionally, add a path exclusion for temporary directories such as C:\Windows\SoftwareDistribution and C:\Users\<User>\AppData\Local\Temp to prevent noise from transient extraction activities.

• Scenario: Enterprise Backup Agent Scans

  • Context: The Veeam or Commvault backup agent performs a scheduled full