PrincessSandyv10eMiNENCEProcessPatcherPatch

Hunt Hypothesis

This detection identifies adversary behavior where malicious processes are injected or patched into legitimate system binaries to evade standard security controls and maintain persistence within the environment. A SOC team should proactively hunt for this activity in Azure Sentinel because process patching is a sophisticated evasion technique that often bypasses traditional signature-based defenses, requiring behavioral analysis to uncover stealthy threats that might otherwise remain undetected.

YARA Rule

rule PrincessSandyv10eMiNENCEProcessPatcherPatch
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 68 27 11 40 00 E8 3C 01 00 00 6A 00 E8 41 01 00 00 A3 00 20 40 00 8B 58 3C 03 D8 0F B7 43 14 0F B7 4B 06 8D 7C 18 18 81 3F 2E 4C 4F 41 74 0B 83 C7 28 49 75 F2 E9 A7 00 00 00 8B 5F 0C 03 1D 00 20 40 00 89 1D 04 20 40 00 8B FB 83 C7 04 68 4C 20 40 00 68 08 }

condition:
		$a0
}

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 PrincessSandyv10eMiNENCE Process Patcher detection rule, along with targeted filters and exclusions:

• Scenario: Microsoft Office Click-to-Run Updates

  • Context: The OfficeClickToRun.exe or Setup.exe process frequently patches its own binaries in the background to apply feature updates without user intervention. This behavior mimics the “Process Patcher” signature by modifying executable headers and injecting code into running Office processes (e.g., WINWORD.EXE, EXCEL.EXE).
  • Filter/Exclusion: Create an exclusion rule for the parent process image path containing \Microsoft Office ClickToRun\ or specific file hashes of known Microsoft update binaries. Additionally, filter alerts where the target process is a member of the OfficeClickToRun family and the action occurs during standard business hours (08:00–18:00).

• Scenario: Antivirus Engine Real-Time Scanning

  • Context: Enterprise Endpoint Protection suites like CrowdStrike Falcon, Carbon Black, or Symantec Endpoint Protection often utilize a “Process Patching” mechanism to inject their scanning agents into new processes. When the antivirus engine updates its own definition files or patches the memory of a running process, it triggers this YARA rule due to similar memory manipulation patterns.
  • Filter/Exclusion: Exclude alerts where the parent process is identified as FalconSensor.exe, ccSvcHst.exe (Symantec), or cb.exe. Implement a logic check that suppresses the alert if the “Patcher” process belongs to a trusted security vendor group and the file being patched is located within the antivirus installation directory.

• Scenario: Scheduled System Health & Patching Jobs

  • Context: Automated maintenance