PUA - RunXCmd Execution — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2022-01-24 / 2023-02-14.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: a60d2eb78d0a8a5143034012d12863c3fb905ab28180bc66cc04ddb6afe8dc56

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: PUA - RunXCmd Execution
id: 93199800-b52a-4dec-b762-75212c196542
status: test
description: Detects the use of the RunXCmd tool to execute commands with System or TrustedInstaller accounts
references:
    - https://www.d7xtech.com/free-software/runx/
    - https://www.winhelponline.com/blog/run-program-as-system-localsystem-account-windows/
author: Florian Roth (Nextron Systems)
date: 2022-01-24
modified: 2023-02-14
tags:
    - attack.execution
    - attack.t1569.002
    - attack.s0029
logsource:
    category: process_creation
    product: windows
detection:
    selection_account:
        CommandLine|contains:
            - ' /account=system '
            - ' /account=ti '
    selection_exec:
        CommandLine|contains: '/exec='
    condition: all of selection_*
falsepositives:
    - Legitimate use by administrators
level: high

Original YAML and metadata in JSON

False positives

• Legitimate use by administrators

Source references

• https://www.d7xtech.com/free-software/runx/
• https://www.winhelponline.com/blog/run-program-as-system-localsystem-account-windows/