Disable IPv6 Addressing on IPv6 Interfaces by Default

An XCCDF Rule

Description

To disable support for (ipv6) addressing on interfaces by default add the following line to /etc/sysctl.d/ipv6.conf (or another file in /etc/sysctl.d):

net.ipv6.conf.default.disable_ipv6 = 1

This disables IPv6 on network interfaces by default as other services and system functionality require the IPv6 stack loaded to work.

Rationale

Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.

ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_disable_ipv6
Severity: Medium
References: BP28(R13)

11 14 3 9

BAI10.01 BAI10.02 BAI10.03 BAI10.05 DSS05.02 DSS05.05 DSS06.06

3.1.20

CCI-001551

4.3.3.5.1 4.3.3.5.2 4.3.3.5.3 4.3.3.5.4 4.3.3.5.5 4.3.3.5.6 4.3.3.5.7 4.3.3.5.8 4.3.3.6.1 4.3.3.6.2 4.3.3.6.3 4.3.3.6.4 4.3.3.6.5 4.3.3.6.6 4.3.3.6.7 4.3.3.6.8 4.3.3.6.9 4.3.3.7.1 4.3.3.7.2 4.3.3.7.3 4.3.3.7.4 4.3.4.3.2 4.3.4.3.3

SR 1.1 SR 1.10 SR 1.11 SR 1.12 SR 1.13 SR 1.2 SR 1.3 SR 1.4 SR 1.5 SR 1.6 SR 1.7 SR 1.8 SR 1.9 SR 2.1 SR 2.2 SR 2.3 SR 2.4 SR 2.5 SR 2.6 SR 2.7 SR 7.6

A.12.1.2 A.12.5.1 A.12.6.2 A.14.2.2 A.14.2.3 A.14.2.4 A.9.1.2

CM-6(a) CM-7(a) CM-7(b)

PR.IP-1 PR.PT-3
Updated: about 1 year ago

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.default.disable_ipv6.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_disable_ipv6

- name: Comment out any occurrences of net.ipv6.conf.default.disable_ipv6 from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.default.disable_ipv6
    replace: '#net.ipv6.conf.default.disable_ipv6'
  loop: '{{ find_sysctl_d.files }}'
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_disable_ipv6

- name: Ensure sysctl net.ipv6.conf.default.disable_ipv6 is set to 1
  sysctl:
    name: net.ipv6.conf.default.disable_ipv6
    value: '1'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_disable_ipv6

Disable IPv6 Addressing on IPv6 Interfaces by Default

Description

Rationale

Remediation - Ansible