Enable Smartcards in SSSD

An XCCDF Rule

Description

SSSD should be configured to authenticate access to the system using smart cards. To enable smart cards in SSSD, set pam_cert_auth to True under the [pam] section in /etc/sssd/sssd.conf. For example:

[pam]
pam_cert_auth = True

Rationale

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multi-Factor Authentication (MFA) solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

ID: xccdf_org.ssgproject.content_rule_sssd_enable_smartcards
Severity: Medium
References: CCI-000765 CCI-000766 CCI-000767 CCI-000768 CCI-001954

0421 0422 0431 0974 1173 1401 1504 1505 1546 1557 1558 1559 1560 1561

Req-8.3

8.4

SRG-OS-000105-GPOS-00052 SRG-OS-000106-GPOS-00053 SRG-OS-000107-GPOS-00054 SRG-OS-000108-GPOS-00055 SRG-OS-000375-GPOS-00160
Updated: about 1 year ago

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-8.3
  - PCI-DSSv4-8.4  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Test for domain group
  command: grep '^\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
  register: test_grep_domain
  ignore_errors: true
  changed_when: false
  check_mode: false
  when:
  - '"sssd-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - PCI-DSS-Req-8.3
  - PCI-DSSv4-8.4
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Add default domain group (if no domain there)
  ini_file:
    path: /etc/sssd/sssd.conf
    section: '{{ item.section }}'
    option: '{{ item.option }}'
    value: '{{ item.value }}'
    create: true
    mode: 384
  with_items:
  - section: sssd
    option: domains
    value: default
  - section: domain/default
    option: id_provider
    value: files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - test_grep_domain.stdout is defined
  - test_grep_domain.stdout | length < 1
  tags:
  - PCI-DSS-Req-8.3
  - PCI-DSSv4-8.4
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Enable Smartcards in SSSD
  ini_file:
    dest: /etc/sssd/sssd.conf
    section: pam
    option: pam_cert_auth
    value: 'True'
    create: true
    mode: 384
  when:
  - '"sssd-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - PCI-DSS-Req-8.3
  - PCI-DSSv4-8.4
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)umask u=rw,go=

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/sssd/sssd.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[pam\]([^\n\[]*\n+)+?[[:space:]]*pam_cert_auth" "$f"; then
            sed -i "s/pam_cert_auth[^(\n)]*/pam_cert_auth = True/" "$f"
            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[pam\]" "$f"; then
            sed -i "/[[:space:]]*\[pam\]/a pam_cert_auth = True" "$f"
            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/sssd/sssd.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"
    echo -e "[pam]\npam_cert_auth = True" >> "$file"
fi

umask $OLD_UMASK

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

Enable Smartcards in SSSD

Description

Rationale

Remediation - Ansible

Remediation - Shell Script