Sigma Rule Library

Persistence Via Sudoers.d Files

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.

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Detection logic

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_*

Raw YAML

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

False positives

  • Creation of legitimate files in sudoers.d folder as part of administrator work

References

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