Disable Samba

An XCCDF Rule

Description

The smb service can be disabled with the following command:

$ sudo systemctl mask --now smb.service

Rationale

Running a Samba server provides a network-based avenue of attack, and should be disabled if not needed.

ID: xccdf_org.ssgproject.content_rule_service_smb_disabled
Severity: Low
References: CCI-001436

2.2.13

CCE-92250-0
Updated: 5 days ago

include disable_smb

class disable_smb {
  service {'smb':
    enable => false,
    ensure => 'stopped',  }
}


[customizations.services]
masked = ["smb"]

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CCE-92250-0
  - disable_strategy  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - service_smb_disabled

- name: Disable Samba - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel-default" in ansible_facts.packages'
  tags:
  - CCE-92250-0
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - service_smb_disabled

- name: Disable Samba - Ensure smb.service is Masked
  ansible.builtin.systemd:
    name: smb.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel-default" in ansible_facts.packages'
  - service_exists.stdout_lines is search("smb.service", multiline=True)
  tags:
  - CCE-92250-0
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - service_smb_disabled

- name: Unit Socket Exists - smb.socket
  ansible.builtin.command: systemctl -q list-unit-files smb.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel-default" in ansible_facts.packages'
  tags:
  - CCE-92250-0
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - service_smb_disabled

- name: Disable Samba - Disable Socket smb
  ansible.builtin.systemd:
    name: smb.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel-default" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("smb.socket", multiline=True)
  tags:
  - CCE-92250-0
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - service_smb_disabled

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel-default; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'smb.service'
"$SYSTEMCTL_EXEC" disable 'smb.service'"$SYSTEMCTL_EXEC" mask 'smb.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files smb.socket; then
    "$SYSTEMCTL_EXEC" stop 'smb.socket'
    "$SYSTEMCTL_EXEC" mask 'smb.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'smb.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Disable Samba

Description

Rationale

Remediation - Puppet

Remediation - OS Build Blueprint

Remediation - Ansible

Remediation - Shell Script