sigmamediumHunting

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.

MITRE ATT&CK

T1548.003

privilege-escalationpersistence

Detection Query

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_*

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2022-07-05

Data Sources

linuxFile Events

Platforms

linux

References

https://github.com/h3xduck/TripleCross/blob/1f1c3e0958af8ad9f6ebe10ab442e75de33e91de/apps/deployer.sh

Tags

attack.privilege-escalationattack.persistenceattack.t1548.003

Raw Content

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