Password Policy Discovery - Linux — Sigma Rule

Rule metadata and linked tags

Author: Ömer Günal, oscd.community, Pawel Mazur. Source status: stable; severity: low. Source dates: 2020-10-08 / 2024-12-01.

{
  "product": "linux",
  "service": "auditd"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6946c5790868c7451cf21b344c5ebafd2fc60349f31c43fd5f8f92fbbcd2fef2

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: Password Policy Discovery - Linux
id: ca94a6db-8106-4737-9ed2-3e3bb826af0a
status: stable
description: Detects password policy discovery commands
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1201/T1201.md
    - https://linux.die.net/man/1/chage
    - https://man7.org/linux/man-pages/man1/passwd.1.html
    - https://superuser.com/questions/150675/how-to-display-password-policy-information-for-a-user-ubuntu
author: Ömer Günal, oscd.community, Pawel Mazur
date: 2020-10-08
modified: 2024-12-01
tags:
    - attack.discovery
    - attack.t1201
logsource:
    product: linux
    service: auditd
detection:
    selection_files:
        type: 'PATH'
        name:
            - '/etc/login.defs'
            - '/etc/pam.d/auth'
            - '/etc/pam.d/common-account'
            - '/etc/pam.d/common-auth'
            - '/etc/pam.d/common-password'
            - '/etc/pam.d/system-auth'
            - '/etc/security/pwquality.conf'
    selection_chage:
        type: 'EXECVE'
        a0: 'chage'
        a1:
            - '--list'
            - '-l'
    selection_passwd:
        type: 'EXECVE'
        a0: 'passwd'
        a1:
            - '-S'
            - '--status'
    condition: 1 of selection_*
falsepositives:
    - Legitimate administration activities
level: low

Original YAML and metadata in JSON

False positives

• Legitimate administration activities

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1201/T1201.md
• https://linux.die.net/man/1/chage
• https://man7.org/linux/man-pages/man1/passwd.1.html
• https://superuser.com/questions/150675/how-to-display-password-policy-information-for-a-user-ubuntu