Add nosuid Option to Removable Media Partitions

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The nosuid mount option prevents set-user-identifier (SUID) and set-group-identifier (SGID) permissions from taking effect. These permissions allow users to execute binaries with the same permissions as the owner and group of the file respectively. Users should not be allowed to introduce SUID and SGID files into the system via partitions mounted from removeable media. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of

any removable media partitions.


The presence of SUID and SGID executables should be tightly controlled. Allowing users to introduce SUID or SGID binaries from partitions mounted off of removable media would allow them to introduce their own highly-privileged programs.


Shell script

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


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

var_removable_partition='<xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_removable_partition" use="legacy"/>'


if grep -q $device_regex /etc/fstab ; then
    previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
    sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
    echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2

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

Ansible playbook

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

- name: XCCDF Value var_removable_partition # promote to variable
    var_removable_partition: !!str <xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_removable_partition" use="legacy"/>
    - always

- name: Ensure permission nosuid are set on var_removable_partition
    path: /etc/fstab
    regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
    backrefs: true
    line: \1 \2 \3 \4,nosuid \5
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - CCE-80148-0
  - DISA-STIG-RHEL-07-021010
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_nosuid_removable_partitions
  - no_reboot_needed