Wmiexec Default Output File — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: critical. Source dates: 2022-06-02 / 2023-03-08.

{
  "category": "file_event",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: ca93d942f56ca19d64e1155f6b872242430d90878cae6b0de7f908e273b21187

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Wmiexec Default Output File
id: 8d5aca11-22b3-4f22-b7ba-90e60533e1fb
status: test
description: Detects the creation of the default output filename used by the wmiexec tool
references:
    - https://www.crowdstrike.com/blog/how-to-detect-and-prevent-impackets-wmiexec/
    - https://github.com/fortra/impacket/blob/f4b848fa27654ca95bc0f4c73dbba8b9c2c9f30a/examples/wmiexec.py
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-06-02
modified: 2023-03-08
tags:
    - attack.lateral-movement
    - attack.execution
    - attack.t1047
logsource:
    category: file_event
    product: windows
detection:
    selection:
        - TargetFilename|re: '\\Windows\\__1\d{9}\.\d{1,7}$' # Admin$
        - TargetFilename|re: 'C:\\__1\d{9}\.\d{1,7}$' # C$
        - TargetFilename|re: 'D:\\__1\d{9}\.\d{1,7}$' # D$
    condition: selection
falsepositives:
    - Unlikely
level: critical

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://www.crowdstrike.com/blog/how-to-detect-and-prevent-impackets-wmiexec/
• https://github.com/fortra/impacket/blob/f4b848fa27654ca95bc0f4c73dbba8b9c2c9f30a/examples/wmiexec.py