tElockv070

Hunt Hypothesis

This detection identifies potential file-based threats or specific malware signatures identified by the tElockv070 YARA rule within the Azure Sentinel environment. Proactively hunting for these indicators allows the SOC team to uncover latent infections that may not trigger high-severity alerts, ensuring early identification of low-fidelity threats before they escalate into broader incidents.

YARA Rule

rule tElockv070
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 E8 BD 10 00 00 C3 83 E2 00 F9 75 FA 70 }

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 tElockv070 detection rule in an enterprise environment, including suggested filters and exclusions:

• Scenario: Enterprise Antivirus Engine Scanning

  • Context: The YARA rule likely detects file locking or process injection behaviors common to endpoint protection. Legitimate scans by CrowdStrike Falcon, Microsoft Defender for Endpoint (MDE), or Symantec Endpoint Protection often lock files in the C:\Program Files directory while performing real-time scanning, triggering the rule.
  • Filter/Exclusion: Add a process exclusion for known security vendors.
    • Action: Exclude processes where ImageName contains falcon.sys, MsMpEng.exe, or Symantec.
    • Logic: IF Process.ImageName IN ['C:\Program Files\CrowdStrike\...\FalconService.exe', 'C:\ProgramData\Microsoft\Microsoft Defender Antivirus\bin\MsMpEng.exe'] THEN Exclude

• Scenario: Scheduled System Backup Jobs

  • Context: Automated backup solutions like Veeam Agent, Commvault, or native Windows Task Scheduler jobs often lock database files (e.g., .vmdk, .bak) during the backup window. If these jobs run on standard business hours, they mimic the file locking behavior detected by tElockv070.
  • Filter/Exclusion: Create a time-based and user-based exclusion for service accounts running backups.
    • Action: Exclude events where AccountName is SYSTEM, BackupService, or specific backup account names (e.g., svc-veeam) occurring between 02:00 and 06:00 UTC.
    • Logic: `IF AccountName IN [‘SYSTEM