Ensure All User Initialization Files Have Mode 0740 Or Less Permissive

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Description

Set the mode of the user initialization files to 0740 with the following command:

$ sudo chmod 0740 /home/USER/.INIT_FILE

Rationale

Local initialization files are used to configure the user’s shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

Remediation

Shell script

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

#!/bin/bash

var_user_initialization_files_regex='^\.[\w\- ]+$'


readarray -t interactive_users < <(awk -F: '$3>=1000   {print $1}' /etc/passwd)
readarray -t interactive_users_home < <(awk -F: '$3>=1000   {print $6}' /etc/passwd)
readarray -t interactive_users_shell < <(awk -F: '$3>=1000   {print $7}' /etc/passwd)

USERS_IGNORED_REGEX='nobody|nfsnobody'

for (( i=0; i<"${#interactive_users[@]}"; i++ )); do
    if ! grep -qP "$USERS_IGNORED_REGEX" <<< "${interactive_users[$i]}" && \
        [ "${interactive_users_shell[$i]}" != "/sbin/nologin" ]; then
        
        readarray -t init_files < <(find "${interactive_users_home[$i]}" -maxdepth 1 \
            -exec basename {} \; | grep -P "$var_user_initialization_files_regex")
        for file in "${init_files[@]}"; do
            chmod u-s,g-wxs,o= "${interactive_users_home[$i]}/$file"
        done
    fi
done

Ansible playbook

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

- name: XCCDF Value var_user_initialization_files_regex # promote to variable
  set_fact:
    var_user_initialization_files_regex: !!str ^\.[\w\- ]+$
  tags:
    - always

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Gather
    User Info
  ansible.builtin.getent:
    database: passwd
  tags:
  - CCE-80525-9
  - DISA-STIG-RHEL-07-020710
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Find
    Init Files
  ansible.builtin.find:
    paths: '{{ item.value[4] }}'
    pattern: '{{ var_user_initialization_files_regex }}'
    hidden: true
    use_regex: true
  with_dict: '{{ ansible_facts.getent_passwd }}'
  when:
  - item.value[4] != "/sbin/nologin"
  - item.key not in ["nobody", "nfsnobody"]
  - item.value[1] | int >= 1000
  register: found_init_files
  tags:
  - CCE-80525-9
  - DISA-STIG-RHEL-07-020710
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Fix
    Init Files Permissions
  ansible.builtin.file:
    path: '{{ item.1.path }}'
    mode: u-s,g-wxs,o=
  loop: '{{ q(''ansible.builtin.subelements'', found_init_files.results, ''files'',
    {''skip_missing'': True}) }}'
  tags:
  - CCE-80525-9
  - DISA-STIG-RHEL-07-020710
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy