Configure System Cryptography Policy

이 페이지는 아직 한국어로 제공되지 않습니다. 번역 작업 중입니다.
현재 번역 프로젝트에 대한 질문이나 피드백이 있으신 경우 언제든지 연락주시기 바랍니다.

Description

To configure the system cryptography policy to use ciphers only from the DEFAULT:NO-SHA1 policy, run the following command:

$ sudo update-crypto-policies --set DEFAULT:NO-SHA1

The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied. Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.

Rationale

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data.

Remediation

Shell script

The following script can be run on the host to remediate the issue.

#!/bin/bash

var_system_crypto_policy='DEFAULT:NO-SHA1'




stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?

if test "$rc" = 127; then
	echo "$stderr_of_call" >&2
	echo "Make sure that the script is installed on the remediated system." >&2
	echo "See output of the 'dnf provides update-crypto-policies' command" >&2
	echo "to see what package to (re)install" >&2

	false  # end with an error code
elif test "$rc" != 0; then
	echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
	false  # end with an error code
fi

Ansible playbook

The following playbook can be run with Ansible to remediate the issue.

- name: XCCDF Value var_system_crypto_policy # promote to variable
  set_fact:
    var_system_crypto_policy: !!str DEFAULT:NO-SHA1
  tags:
    - always

- name: Configure System Cryptography Policy - Check current crypto policy (runtime)
  ansible.builtin.command: /usr/bin/update-crypto-policies --show
  register: current_crypto_policy
  changed_when: false
  failed_when: false
  check_mode: false
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Configure System Cryptography Policy - Get mtime of /etc/crypto-policies/config
  ansible.builtin.stat:
    path: /etc/crypto-policies/config
  register: config_file_stat
  changed_when: false
  failed_when: false
  check_mode: false
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Configure System Cryptography Policy - Get mtime of /etc/crypto-policies/state/current
  ansible.builtin.stat:
    path: /etc/crypto-policies/state/current
  register: current_file_stat
  changed_when: false
  failed_when: false
  check_mode: false
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Configure System Cryptography Policy - Check existence of /etc/crypto-policies/back-ends/nss.config
  ansible.builtin.stat:
    path: /etc/crypto-policies/back-ends/nss.config
  register: nss_config_stat
  changed_when: false
  failed_when: false
  check_mode: false
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Configure System Cryptography Policy - Verify that Crypto Policy is Set (runtime)
  ansible.builtin.command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy
    }}
  when: (current_crypto_policy.stdout.strip() != var_system_crypto_policy) or (config_file_stat.stat.exists
    and current_file_stat.stat.exists and config_file_stat.stat.mtime > current_file_stat.stat.mtime)
    or (not nss_config_stat.stat.exists)
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

Warning

The system needs to be rebooted for these changes to take effect.