Linux Keylogging with Pam.d — Sigma Rule

Rule metadata and linked tags

Author: Pawel Mazur. Source status: test; severity: high. Source dates: 2021-05-24 / 2022-12-18.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6d8c21170ae1127d0332decff157db704c6664c96eee4cb956dc3a6d33696eb8

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: Linux Keylogging with Pam.d
id: 49aae26c-450e-448b-911d-b3c13d178dfc
status: test
description: Detect attempt to enable auditing of TTY input
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1056.001/T1056.001.md
    - https://linux.die.net/man/8/pam_tty_audit
    - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sec-configuring_pam_for_auditing
    - https://access.redhat.com/articles/4409591#audit-record-types-2
author: 'Pawel Mazur'
date: 2021-05-24
modified: 2022-12-18
tags:
    - attack.collection
    - attack.credential-access
    - attack.t1003
    - attack.t1056.001
logsource:
    product: linux
    service: auditd
detection:
    selection_path_events:
        type: PATH
        name:
            - '/etc/pam.d/system-auth'
            - '/etc/pam.d/password-auth'
    selection_tty_events:
        type:
            - 'TTY'
            - 'USER_TTY'
    condition: 1 of selection_*
falsepositives:
    - Administrative work
level: high

Original YAML and metadata in JSON

False positives

• Administrative work

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1056.001/T1056.001.md
• https://linux.die.net/man/8/pam_tty_audit
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/security_guide/sec-configuring_pam_for_auditing
• https://access.redhat.com/articles/4409591#audit-record-types-2