Disable the selinuxuser_execstack SELinux Boolean

An XCCDF Rule

Description

By default, the SELinux boolean selinuxuser_execstack is enabled. This setting should be disabled as unconfined executables should not be able to make their stack executable. To disable the selinuxuser_execstack SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execstack off

Rationale

Disabling code execution from the stack blocks buffer overflow attacks.

ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execstack
Severity: Medium
References: 164.308(a)(1)(ii)(D) 164.308(a)(3) 164.308(a)(4) 164.310(b) 164.310(c) 164.312(a) 164.312(e)

CCE-91422-6

R48
Updated: 5 days ago

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CCE-91422-6
  - enable_strategy  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack

- name: Disable the selinuxuser_execstack SELinux Boolean - Ensure policycoreutils
    Installed
  package:
    name: policycoreutils
    state: present
  when: '"kernel-default" in ansible_facts.packages'
  tags:
  - CCE-91422-6
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack

- name: Disable the selinuxuser_execstack SELinux Boolean - Ensure Additional Packages
    Installed
  become: true
  package:
    name:
    - policycoreutils-python-utils
    - selinux-tools
    - python3-selinux
    - python3-semanage
    state: present
  when: '"kernel-default" in ansible_facts.packages'
  tags:
  - CCE-91422-6
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack
- name: XCCDF Value var_selinuxuser_execstack # promote to variable
  set_fact:
    var_selinuxuser_execstack: !!str <xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_selinuxuser_execstack" use="legacy"/>
  tags:
    - always

- name: Disable the selinuxuser_execstack SELinux Boolean - Set SELinux Boolean selinuxuser_execstack
    Accordingly
  seboolean:
    name: selinuxuser_execstack
    state: '{{ var_selinuxuser_execstack }}'
    persistent: true
  when:
  - '"kernel-default" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - CCE-91422-6
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel-default; then

zypper install -y "policycoreutils"
zypper install -y "policycoreutils-python-utils"
zypper install -y "selinux-tools"zypper install -y "python3-selinux"
zypper install -y "python3-semanage"


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_execstack='<xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_selinuxuser_execstack" use="legacy"/>'

    setsebool -P selinuxuser_execstack $var_selinuxuser_execstack

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

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

Disable the selinuxuser_execstack SELinux Boolean

Description

Rationale

Remediation - Ansible

Remediation - Shell Script