AHTeamEPProtector03fakePELockNT204FEUERRADER

Hunt Hypothesis

This detection identifies suspicious endpoint activity characterized by fake PE lock mechanisms and specific error patterns that may indicate early-stage fileless or memory-resident malware execution. Proactively hunting for this behavior in Azure Sentinel allows the SOC team to uncover stealthy adversaries evading traditional signature-based defenses before they establish persistence or escalate their impact on critical workloads.

YARA Rule

rule AHTeamEPProtector03fakePELockNT204FEUERRADER
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 90 [46] 90 FF E0 EB 03 CD 20 C7 1E EB 03 CD 20 EA 9C EB 02 EB 01 EB 01 EB 60 EB 03 CD 20 EB EB 01 EB }

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 5 specific false positive scenarios for the AHTeamEPProtector03fakePELockNT204FEUERRADER detection rule, including suggested filters and exclusions:

• Scenario: Microsoft Defender Antivirus (MSRT) Scheduled Scans

  • Context: The Microsoft Malware Protection Service (MsMpSvc) performs daily scheduled scans that often generate temporary PE lock files or error readers during the scanning of large file repositories, mimicking the behavior of a fake PE protector.
  • Filter/Exclusion: Create an exclusion for the process MsMpEng.exe and its child processes when running under the account NT SERVICE\MsMpSvc. Additionally, exclude the specific path C:\ProgramData\Microsoft\Windows Defender\Scans\History from the rule’s scope.

• Scenario: System Center Configuration Manager (SCCM) Software Updates

  • Context: During the deployment of new software packages or Windows updates via SCCM (ccmsetup.exe), the client agent locks configuration files and generates error logs that trigger the “fake PE” signature due to rapid file creation and locking mechanisms.
  • Filter/Exclusion: Exclude processes named ccmexec.exe, wuauserv.exe, and ccmsetup.exe. Add a filter to ignore events originating from the specific SCCM client ID range or exclude the directory C:\Windows\CCM entirely.

• Scenario: Enterprise Backup Solutions (Veeam/Commvault) Snapshot Locking

  • Context: When Veeam Agent or CommCell performs a backup snapshot, it locks active database files and application binaries to ensure consistency. This locking mechanism is often misidentified by the YARA rule as an anomalous PE protection attempt.
  • Filter/Exclusion: Exclude processes `VeeamTransportService