Petite14

Hunt Hypothesis

This detection identifies potential memory-resident threats by leveraging the Petite14 YARA signature to uncover stealthy adversary behaviors that evade traditional file-based scanning. Proactive hunting for this indicator in Azure Sentinel is essential to validate its presence across endpoints and prevent low-severity anomalies from escalating into undetected lateral movement or data exfiltration campaigns.

YARA Rule

rule Petite14
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 66 9C 60 50 8B D8 03 00 68 54 BC 00 00 6A 00 FF 50 14 8B CC }

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 Petite14 detection rule, including suggested filters and exclusions tailored for an enterprise environment:

• Scenario: Scheduled Antivirus Definition Updates

  • Context: The YARA rule triggers when the Microsoft Defender Antivirus service (MsMpEng.exe) or Symantec Endpoint Protection updates its virus definition database. These processes often spawn child processes that match the Petite14 signature while unpacking large compressed update packages in the C:\ProgramData\Microsoft\Windows Defender directory.
  • Suggested Filter: Create an exclusion based on the parent process name and path. Exclude alerts where ParentProcessName is MsMpEng.exe or Symantec Endpoint Protection AND FilePath contains \Microsoft\Windows Defender\ or \Program Files\Symantec\.

• Scenario: Automated Patch Deployment via SCCM/Intune

  • Context: During nightly maintenance windows, the System Center Configuration Manager (SCCM) or Microsoft Intune agent (ccmexec.exe) executes software deployment tasks. When installing updates for enterprise applications like Adobe Acrobat or Java, the installer extracts temporary files that match the Petite14 logic, causing a spike in detections during the 2:00 AM – 4:00 AM window.
  • Suggested Filter: Implement a time-based exclusion combined with a process hash whitelist. Exclude alerts occurring between 02:00 and 04:00 on weekdays where the ProcessName is ccmexec.exe or Microsoft.IntuneManagementExtension.

• Scenario: Enterprise Backup Agent Operations

  • Context: The Veeam Backup & Replication agent (vrbroker.exe) performs incremental backups of user profiles and shared drives. As it reads and