tElockv060

Hunt Hypothesis

This hypothesis targets potential instances of the tElockv060 malware family, which may indicate an adversary attempting to establish a foothold or execute malicious payloads within the environment. Proactively hunting for this signature in Azure Sentinel allows the SOC team to identify low-severity threats early, preventing them from escalating into more complex attacks or data exfiltration events.

YARA Rule

rule tElockv060
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E9 00 00 00 00 60 E8 00 00 00 00 58 83 C0 08 }

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

• Scenario: A security team performs a scheduled full-disk encryption audit using BitLocker Management Console (manage-bde) or PowerShell’s Get-BitLockerVolume cmdlets on a fleet of Windows 10/11 endpoints. The YARA rule may match the specific memory footprint or binary characteristics of the BdeKey.exe or related service processes during the key retrieval or status check phase.

  • Filter/Exclusion: Exclude processes where the parent process is powershell.exe or pwsh.exe and the command line contains Get-BitLockerVolume or manage-bde. Additionally, exclude if the process path is C:\Windows\System32\BdeKey.exe or C:\Program Files\Windows Defender\... (if applicable to the specific YARA match).

• Scenario: An IT administrator deploys a new version of Microsoft Defender Antivirus or updates the Windows Update client via Group Policy or Configuration Manager (SCCM/MECM). The update process temporarily loads specific DLLs or executes wuauclt.exe or trustedinstaller.exe in a way that matches the YARA signature’s structural or string-based criteria (e.g., matching specific version strings or module layouts).

  • Filter/Exclusion: Exclude if the process name is wuauclt.exe, trustedinstaller.exe, or svchost.exe (with the WU service) and the parent process is services.exe or svchost.exe. Verify the file version matches the known good build number for the current OS release.

• Scenario: A developer or QA engineer runs a local Visual Studio or JetBrains Rider instance with a C++/C# project that includes a custom library or dependency named similarly to the target (e.g., tElock.dll