Disable Network File System (nfs)

An XCCDF Rule

Description

The Network File System (NFS) service allows remote hosts to mount and interact with shared filesystems on the local system. If the local system is not designated as a NFS server then this service should be disabled. The nfs-server service can be disabled with the following command:

$ sudo systemctl mask --now nfs-server.service

Rationale

Unnecessary services should be disabled to decrease the attack surface of the system.

ID: xccdf_org.ssgproject.content_rule_service_nfs_disabled
Severity: Unknown
References: 11 12 14 15 16 18 3 5

DSS05.02 DSS05.04 DSS05.05 DSS05.07 DSS06.03 DSS06.06

4.3.3.2.2 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

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

A.6.1.2 A.7.1.1 A.9.1.2 A.9.2.1 A.9.2.3 A.9.4.1 A.9.4.4 A.9.4.5

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

PR.AC-4 PR.AC-6 PR.PT-3

2.2.9
Updated: over 1 year ago

Remediation Templates

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0    systemd:
      units:
      - name: nfs-server.service
        enabled: false
        mask: true
      - name: nfs-server.socket
        enabled: false
        mask: true

[customizations.services]
disabled = ["nfs-server"]

include disable_nfs-server
class disable_nfs-server {
  service {'nfs-server':
    enable => false,
    ensure => 'stopped',
  }
}

- name: Block Disable service nfs-server
  block:
  - name: Disable service nfs-server
    block:

    - name: Disable service nfs-server      systemd:
        name: nfs-server.service
        enabled: 'no'
        state: stopped
        masked: 'yes'
    rescue:

    - name: Intentionally ignored previous 'Disable service nfs-server' failure, service
        was already disabled
      meta: noop
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_nfs_disabled
  - unknown_severity

- name: Unit Socket Exists - nfs-server.socket
  command: systemctl -q list-unit-files nfs-server.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_nfs_disabled
  - unknown_severity

- name: Disable socket nfs-server
  systemd:
    name: nfs-server.socket
    enabled: 'no'
    state: stopped
    masked: 'yes'
  when:
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - socket_file_exists.stdout_lines is search("nfs-server.socket",multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_nfs_disabled
  - unknown_severity

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'nfs-server.service'
"$SYSTEMCTL_EXEC" disable 'nfs-server.service'
"$SYSTEMCTL_EXEC" mask 'nfs-server.service'# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files nfs-server.socket; then
    "$SYSTEMCTL_EXEC" stop 'nfs-server.socket'
    "$SYSTEMCTL_EXEC" mask 'nfs-server.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 'nfs-server.service' || true

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

Disable Network File System (nfs)

Description

Rationale

Remediation Templates

A Kubernetes Patch

OS Build Blueprint

A Puppet Snippet

An Ansible Snippet

A Shell Script