Verify that System Executables Have Restrictive Permissions

An XCCDF Rule

Description

System executables are stored in the following directories by default:

/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin

All files in these directories should not be group-writable or world-writable. If any file FILE in these directories is found to be group-writable or world-writable, correct its permission with the following command:

$ sudo chmod go-w FILE

Rationale

System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.

ID: xccdf_org.ssgproject.content_rule_file_permissions_binary_dirs
Severity: Medium
References: 12 13 14 15 16 18 3 5

APO01.06 DSS05.04 DSS05.07 DSS06.02

CCI-001499

4.3.3.7.3

SR 2.1 SR 5.2

A.10.1.1 A.11.1.4 A.11.1.5 A.11.2.1 A.13.1.1 A.13.1.3 A.13.2.1 A.13.2.3 A.13.2.4 A.14.1.2 A.14.1.3 A.6.1.2 A.7.1.1 A.7.1.2 A.7.3.1 A.8.2.2 A.8.2.3 A.9.1.1 A.9.1.2 A.9.2.3 A.9.4.1 A.9.4.4 A.9.4.5

CIP-003-8 R5.1.1 CIP-003-8 R5.3 CIP-004-6 R2.3 CIP-007-3 R2.1 CIP-007-3 R2.2 CIP-007-3 R2.3 CIP-007-3 R5.1 CIP-007-3 R5.1.1 CIP-007-3 R5.1.2

AC-6(1) CM-5(6) CM-5(6).1 CM-6(a)

PR.AC-4 PR.DS-5

SRG-OS-000259-GPOS-00100
Updated: about 1 year ago

- name: Read list of world and group writable system executables
  ansible.builtin.command: find /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin
    /usr/libexec -perm /022 -type f
  register: world_writable_library_files
  changed_when: false
  failed_when: false  check_mode: false
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-5(6)
  - NIST-800-53-CM-5(6).1
  - NIST-800-53-CM-6(a)
  - file_permissions_binary_dirs
  - medium_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Remove world/group writability of system executables
  ansible.builtin.file:
    path: '{{ item }}'
    mode: go-w
    state: file
  with_items: '{{ world_writable_library_files.stdout_lines }}'
  when: world_writable_library_files.stdout_lines | length > 0
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-5(6)
  - NIST-800-53-CM-5(6).1
  - NIST-800-53-CM-6(a)
  - file_permissions_binary_dirs
  - medium_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Verify that System Executables Have Restrictive Permissions

Description

Rationale

Remediation - Ansible