Prevent Login to Accounts With Empty Password

An XCCDF Rule

Description

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the nullok in password authentication configurations in /etc/pam.d/ to prevent logins with empty passwords.

warning alert: Warning

If the system relies on authselect tool to manage PAM settings, the remediation will also use authselect tool. However, if any manual modification was made in PAM files, the authselect integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. Note that this rule is not applicable for systems running within a container. Having user with empty password within a container is not considered a risk, because it should not be possible to directly login into a container anyway.

Rationale

If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

ID: xccdf_org.ssgproject.content_rule_no_empty_passwords
Severity: High
References: 1 12 13 14 15 16 18 3 5

5.5.2

APO01.06 DSS05.04 DSS05.05 DSS05.07 DSS05.10 DSS06.02 DSS06.03 DSS06.10

3.1.1 3.1.5

CCI-000366

164.308(a)(1)(ii)(B) 164.308(a)(7)(i) 164.308(a)(7)(ii)(A) 164.310(a)(1) 164.310(a)(2)(i) 164.310(a)(2)(ii) 164.310(a)(2)(iii) 164.310(b) 164.310(c) 164.310(d)(1) 164.310(d)(2)(iii)

4.3.3.2.2 4.3.3.5.1 4.3.3.5.2 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 4.3.3.7.2 4.3.3.7.3 4.3.3.7.4

SR 1.1 SR 1.10 SR 1.2 SR 1.3 SR 1.4 SR 1.5 SR 1.7 SR 1.8 SR 1.9 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.18.1.4 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.9.2.1 A.9.2.2 A.9.2.3 A.9.2.4 A.9.2.6 A.9.3.1 A.9.4.1 A.9.4.2 A.9.4.3 A.9.4.4 A.9.4.5

CM-6(a) IA-5(1)(a) IA-5(c)

PR.AC-1 PR.AC-4 PR.AC-6 PR.AC-7 PR.DS-5

FIA_UAU.1

Req-8.2.3

SRG-OS-000480-GPOS-00227

SLES-12-010231

SV-217125r603262_rule

CCE-83039-8

8.3.1
Updated: about 1 year ago

- name: Find files in /etc/pam.d/ with password auth
  find:
    paths: /etc/pam.d
    contains: .*pam_unix\.so.*nullok.*
    recurse: true
  register: find_pam_conf_files_result  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - CCE-83039-8
  - CJIS-5.5.2
  - DISA-STIG-SLES-12-010231
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

- name: Prevent Log In to Accounts with Empty Password
  replace:
    dest: '{{ item.path }}'
    regexp: nullok
  with_items: '{{ find_pam_conf_files_result.files }}'
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - CCE-83039-8
  - CJIS-5.5.2
  - DISA-STIG-SLES-12-010231
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

PAM_PATH="/etc/pam.d/"
NULLOK_FILES=$(grep -rl ".*pam_unix\\.so.*nullok.*" ${PAM_PATH})
for FILE in ${NULLOK_FILES}; do   sed --follow-symlinks -i 's/\<nullok\>//g' ${FILE}
done

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

Prevent Login to Accounts With Empty Password

Description

Rationale

Remediation - Ansible

Remediation - Shell Script