VterminalV10XLeiPeng

Hunt Hypothesis

This rule detects the presence of the VterminalV10XLeiPeng YARA signature, which typically indicates the execution of a specific malicious script or payload associated with the Vterminal toolset. Proactively hunting for this indicator allows the SOC team to identify low-severity footholds or lateral movement attempts in Azure Sentinel before they escalate into more significant compromise events.

YARA Rule

rule VterminalV10XLeiPeng
{
      meta:
		author="malware-lu"
strings:
		$a0 = { E8 00 00 00 00 58 05 [4] 9C 50 C2 04 00 }

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 DevOps engineer runs a custom Python-based utility script (e.g., deploy_helper.py) that embeds a base64-encoded payload or uses a specific string pattern (like vterm or xlei) to initialize a lightweight terminal session for remote debugging, triggering the YARA signature due to the embedded string or code structure.

  • Filter/Exclusion: Exclude files located in specific development directories (e.g., C:\Dev\Projects\*, D:\Scripts\*) or exclude processes where the parent process is python.exe or python3.exe and the file extension is .py or .pyc.

• Scenario: An IT administrator uses a legitimate third-party terminal multiplexer or SSH client (such as tmux, screen, or a custom wrapper for plink.exe) that has been patched or compiled with a specific library version matching the “Vterminal” or “XLei” identifier in its binary strings, causing a match during a routine system update or deployment.

  • Filter/Exclusion: Exclude known signed binaries from trusted vendors (e.g., tmux.exe, plink.exe, putty.exe) by checking the Authenticode signature or excluding specific file paths like C:\Program Files\Tmux\ or C:\Tools\SSH\.

• Scenario: A scheduled backup or log rotation job (e.g., logrotate or a custom PowerShell script) processes log files that contain the string “vterminal” or “xlei” as part of a debug header or version tag from a specific application (e.g., a legacy internal tool named “VTerm”), causing the YARA rule to match the file content during scanning.

  • Filter/Exclusion: Exclude files with specific extensions (.log, .txt, .json) if they are located