---
policy: ABCD Benchmark for securing Linux systems with levels
title: ABCD Benchmark for securing Linux systems with levels
id: abcd-levels
version: 1.2.3
source: https://www.abcd.com/linux.pdf
levels:
  - id: low
  - id: medium
    inherits_from:
      - low
  - id: high
    inherits_from:
      - medium

controls:
  - id: S1
    title: User session timeout

  - id: S2
    levels:
      - low
    rules:
      - var_password_pam_minlen=1

  - id: S3
    levels:
      - medium

  - id: S4
    title: Configure authentication
    controls:
      - id: S4.a
        title: Disable administrator accounts
        levels:
          - low

      - id: S4.b
        title: Enforce password quality standards
        levels:
          - high
        rules:
          - var_password_pam_minlen=2

  # S5, S6 and S7 are used to test if level inheritance is working correctly
  # when multiple levels select the same rule
  - id: S5
    title: Default Crypto Policy
    levels:
      - low
    rules:
      - configure_crypto_policy
      - var_system_crypto_policy=default_policy

  - id: S6
    title: FIPS Crypto Policy
    levels:
      - medium
    rules:
      - file_groupownership_sshd_private_key
      - var_system_crypto_policy=fips

  - id: S7
    title: Future Crypto Policy
    levels:
      - high
    rules:
      - sshd_set_keepalive
      - var_system_crypto_policy=future
