Access of Sudoers File Content — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: medium. Source dates: 2022-06-20 / 2025-06-04.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2e9a5c54d49a0c7c42e50fe207b1cdfeaf6cca053212768c8cc145232f730e1f

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: Access of Sudoers File Content
id: 0f79c4d2-4e1f-4683-9c36-b5469a665e06
status: test
description: Detects the execution of a text-based file access or inspection utilities to read the content of /etc/sudoers in order to potentially list all users that have sudo rights.
references:
    - https://github.com/sleventyeleven/linuxprivchecker/
author: Florian Roth (Nextron Systems)
date: 2022-06-20
modified: 2025-06-04
tags:
    - attack.reconnaissance
    - attack.t1592.004
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith:
            - '/cat'
            - '/ed'
            - '/egrep'
            - '/emacs'
            - '/fgrep'
            - '/grep'
            - '/head'
            - '/less'
            - '/more'
            - '/nano'
            - '/tail'
        CommandLine|contains: ' /etc/sudoers'
    condition: selection
falsepositives:
    - Legitimate administration activities
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate administration activities

Source references

• https://github.com/sleventyeleven/linuxprivchecker/