Linux Password Policy Discovery via chage and passwd Commands

Identifies Linux password policy discovery by running chage/waswo with status arguments and reading common password policy files.

FreeReviewedSigma · Low · v3
Product
linux
Service
auditd
Author
Ömer Günal, oscd.community, Pawel Mazur (SigmaHQ), DRL 1.1
Published
2020-10-08
Updated
2026-07-31
title: Linux Password Policy Discovery via chage and passwd Commands
id: 03e03609-39da-4346-b317-c59c818efd4c
status: stable
description: This rule identifies attempts to discover Linux password policy information by executing chage or passwd with options that reveal account and password status. Attackers use this knowledge to tailor password-guessing or account-manipulation attempts to local policy constraints. Detection relies on auditd process execution telemetry (EXECVE) for the specific binaries and relevant configuration file names.
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
  - https://github.com/SigmaHQ/sigma/blob/master/rules/linux/auditd/lnx_auditd_password_policy_discovery.yml
author: Ömer Günal, oscd.community, Pawel Mazur, Huntrule Team
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
license: DRL-1.1
related:
  - id: ca94a6db-8106-4737-9ed2-3e3bb826af0a
    type: derived