ansible-linux-infra/roles/cis_hardening/tasks/main.yml

---
- name: Include OS-family-specific variables
  ansible.builtin.include_vars: "{{ item }}"
  with_first_found:
    - "{{ ansible_facts['os_family'] }}.yml"
    - "default.yml"
  tags: [cis_hardening, always]

- name: Disable unneeded filesystem kernel modules
  ansible.builtin.copy:
    dest: /etc/modprobe.d/cis-disable-filesystems.conf
    owner: root
    group: root
    mode: "0644"
    content: |
      # {{ ansible_managed }}
      {% for fs in cis_disable_filesystems %}
      install {{ fs }} /bin/true
      {% endfor %}
  tags: [cis_hardening]

- name: Set kernel/network sysctl hardening parameters
  ansible.posix.sysctl:
    name: "{{ item.name }}"
    value: "{{ item.value }}"
    sysctl_set: true
    state: present
    reload: true
  loop:
    - { name: "net.ipv4.ip_forward", value: "0" }
    - { name: "net.ipv4.conf.all.send_redirects", value: "0" }
    - { name: "net.ipv4.conf.all.accept_redirects", value: "0" }
    - { name: "net.ipv4.conf.all.accept_source_route", value: "0" }
    - { name: "net.ipv4.conf.all.log_martians", value: "1" }
    - { name: "net.ipv4.icmp_echo_ignore_broadcasts", value: "1" }
    - { name: "kernel.randomize_va_space", value: "2" }
    - { name: "fs.suid_dumpable", value: "0" }
  tags: [cis_hardening]

- name: Enable strict reverse-path filtering (CIS Level 2)
  ansible.posix.sysctl:
    name: "net.ipv4.conf.all.rp_filter"
    value: "1"
    sysctl_set: true
    state: present
    reload: true
  when: cis_level | int >= 2
  tags: [cis_hardening]

- name: Harden /tmp mount options (noexec,nosuid,nodev)
  ansible.posix.mount:
    path: /tmp
    src: tmpfs
    fstype: tmpfs
    opts: "defaults,rw,nosuid,nodev,noexec,relatime"
    state: mounted
  tags: [cis_hardening]

- name: Bind and harden /var/tmp (CIS Level 2)
  ansible.posix.mount:
    path: /var/tmp
    src: /tmp
    fstype: none
    opts: "bind,nosuid,nodev,noexec"
    state: mounted
  when: cis_level | int >= 2
  tags: [cis_hardening]

- name: Disable additional kernel modules (CIS Level 2)
  ansible.builtin.copy:
    dest: /etc/modprobe.d/cis-disable-level2-modules.conf
    owner: root
    group: root
    mode: "0644"
    content: |
      # {{ ansible_managed }}
      {% for mod in cis_disable_modules_level2 %}
      install {{ mod }} /bin/true
      {% endfor %}
  when: cis_level | int >= 2
  tags: [cis_hardening]

- name: Disable core dumps
  ansible.builtin.copy:
    dest: /etc/security/limits.d/99-cis-disable-coredumps.conf
    owner: root
    group: root
    mode: "0644"
    content: |
      # {{ ansible_managed }}
      * hard core 0
  tags: [cis_hardening]

- name: Enforce default umask
  ansible.builtin.copy:
    dest: /etc/profile.d/99-cis-umask.sh
    owner: root
    group: root
    mode: "0644"
    content: |
      # {{ ansible_managed }}
      umask {{ cis_umask }}
  tags: [cis_hardening]

- name: Set shell auto-logout timeout (TMOUT)
  ansible.builtin.copy:
    dest: /etc/profile.d/99-cis-tmout.sh
    owner: root
    group: root
    mode: "0644"
    content: |
      # {{ ansible_managed }}
      TMOUT={{ cis_shell_tmout_seconds }}
      readonly TMOUT
      export TMOUT
  tags: [cis_hardening]

- name: Mask Ctrl-Alt-Del reboot target
  ansible.builtin.systemd:
    name: ctrl-alt-del.target
    masked: true
  when: cis_disable_ctrl_alt_del | bool
  tags: [cis_hardening]

- name: Find world-writable directories missing the sticky bit
  ansible.builtin.shell: >
    set -o pipefail;
    df --local -P | awk '{if (NR!=1) print $6}' |
    xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null
  register: cis_hardening_sticky_bit_dirs
  changed_when: false
  when: cis_sticky_bit_enforce | bool
  tags: [cis_hardening]

- name: Apply sticky bit to world-writable directories
  ansible.builtin.file:
    path: "{{ item }}"
    mode: "a+t"
  loop: "{{ cis_hardening_sticky_bit_dirs.stdout_lines | default([]) }}"
  when: cis_sticky_bit_enforce | bool
  tags: [cis_hardening]

- name: Configure journald persistent storage and size cap
  ansible.builtin.lineinfile:
    path: /etc/systemd/journald.conf
    regexp: "^#?{{ item.key }}="
    line: "{{ item.key }}={{ item.value }}"
  loop:
    - { key: "Storage", value: "persistent" }
    - { key: "SystemMaxUse", value: "{{ cis_journald_max_use }}" }
  when: cis_journald_persistent | bool
  notify: restart systemd-journald
  tags: [cis_hardening]

- name: Schedule weekly report of unowned/ungrouped files
  ansible.builtin.cron:
    name: "Weekly unowned files report"
    weekday: "0"
    hour: "{{ cis_unowned_files_report_cron_hour }}"
    minute: "0"
    job: >-
      /usr/bin/find / -xdev \( -nouser -o -nogroup \) 2>/dev/null |
      /usr/bin/mail -s "Unowned files report {{ inventory_hostname }}" root
    user: root
  when: cis_unowned_files_report_enabled | bool
  tags: [cis_hardening]

- name: Harden /boot mount options in fstab (requires manual review and reboot)
  ansible.builtin.replace:
    path: /etc/fstab
    regexp: '^(\S+\s+/boot\s+\S+\s+)(?!.*nodev)(\S+)(\s+.*)$'
    replace: '\1\2,nodev,nosuid\3'
  when: cis_boot_hardening_enabled | bool
  tags: [cis_hardening]

- name: Deploy baseline auditd rules (logins, time changes, account changes)
  ansible.builtin.template:
    src: audit-baseline.rules.j2
    dest: /etc/audit/rules.d/10-baseline.rules
    owner: root
    group: root
    mode: "0640"
  notify: reload auditd rules
  tags: [cis_hardening]

- name: Deploy extended auditd rules (CIS Level 2)
  ansible.builtin.template:
    src: audit-level2.rules.j2
    dest: /etc/audit/rules.d/20-level2.rules
    owner: root
    group: root
    mode: "0640"
  when: cis_level | int >= 2
  notify: reload auditd rules
  tags: [cis_hardening]

- name: Configure auditd log rotation and disk-space handling
  ansible.builtin.lineinfile:
    path: /etc/audit/auditd.conf
    regexp: "^{{ item.key }}\\s*="
    line: "{{ item.key }} = {{ item.value }}"
  loop:
    - { key: "max_log_file", value: "50" }
    - { key: "max_log_file_action", value: "rotate" }
    - { key: "num_logs", value: "10" }
    - { key: "space_left", value: "10%" }
    - { key: "space_left_action", value: "email" }
    - { key: "admin_space_left", value: "5%" }
    - { key: "admin_space_left_action", value: "halt" }
  notify: restart auditd
  tags: [cis_hardening]

- name: Set login.defs password aging policy
  ansible.builtin.lineinfile:
    path: /etc/login.defs
    regexp: "^{{ item.key }}"
    line: "{{ item.key }}\t{{ item.value }}"
  loop:
    - { key: "PASS_MAX_DAYS", value: "90" }
    - { key: "PASS_MIN_DAYS", value: "1" }
    - { key: "PASS_WARN_AGE", value: "7" }
  tags: [cis_hardening]

- name: Restrict cron/at to authorized users
  ansible.builtin.file:
    path: "{{ item }}"
    state: touch
    owner: root
    group: root
    mode: "0600"
  loop:
    - /etc/cron.allow
    - /etc/at.allow
  tags: [cis_hardening]

- name: Configure GRUB bootloader password (pre-generated PBKDF2 hash)
  ansible.builtin.blockinfile:
    path: /etc/grub.d/40_custom
    marker: "# {mark} ANSIBLE MANAGED BLOCK"
    insertafter: "EOF"
    block: |
      set superusers="{{ grub_bootloader_username }}"
      password_pbkdf2 {{ grub_bootloader_username }} {{ grub_bootloader_password_hash }}
  when:
    - cis_grub_password_enabled | bool
    - grub_bootloader_password_hash | length > 0
  notify: regenerate grub config
  tags: [cis_hardening]

- name: Enable and start auditd
  ansible.builtin.systemd:
    name: auditd
    enabled: true
    state: started
  tags: [cis_hardening]