Persistence Via Sudoers.d Files

Description

Detects the creation or modification of files within the "sudoers.d" directory on Linux systems. Such activity may indicate an attempt to establish or maintain privilege escalation by granting specific users elevated permissions. Unauthorized changes to sudoers files are a common technique used by attackers to persist administrative access.

Query · sigma

selection:
  TargetFilename|startswith: /etc/sudoers.d/
filter_main_dpkg:
  Image|endswith: /usr/bin/dpkg
  TargetFilename: /etc/sudoers.d/README.dpkg-new
condition: selection and not 1 of filter_main_*

Known false positives

  • Creation of legitimate files in sudoers.d folder as part of administrator work
Raw source Persistence Via Sudoers.d Files · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: Persistence Via Sudoers.d Files
id: ddb26b76-4447-4807-871f-1b035b2bfa5d
status: test
description: |
    Detects the creation or modification of files within the "sudoers.d" directory on Linux systems.
    Such activity may indicate an attempt to establish or maintain privilege escalation by granting specific users elevated permissions.
    Unauthorized changes to sudoers files are a common technique used by attackers to persist administrative access.
references:
    - https://github.com/h3xduck/TripleCross/blob/1f1c3e0958af8ad9f6ebe10ab442e75de33e91de/apps/deployer.sh
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-05
modified: 2026-03-18
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1548.003
logsource:
    product: linux
    category: file_event
detection:
    selection:
        TargetFilename|startswith: '/etc/sudoers.d/'
    filter_main_dpkg:
        Image|endswith: '/usr/bin/dpkg'
        TargetFilename: '/etc/sudoers.d/README.dpkg-new'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Creation of legitimate files in sudoers.d folder as part of administrator work
level: medium

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