Verify Group Who Owns /etc/cron.allow file

Docs > Datadog Security > OOTB Rules > Verify Group Who Owns /etc/cron.allow file

Description

If /etc/cron.allow exists, it must be group-owned by crontab. To properly set the group owner of /etc/cron.allow, run the command:

$ sudo chgrp crontab /etc/cron.allow

Rationale

If the owner of the cron.allow file is not set to crontab, the possibility exists for an unauthorized user to view or edit sensitive information.

Remediation

Shell script

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

#!/bin/bash

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}' 'linux-base' 2>/dev/null | grep -q '^installed$'; then

if getent group "crontab" >/dev/null 2>&1; then
  newgroup="crontab"
fi
if [[ -z ${newgroup} ]]; then
  echo "crontab is not a defined group on the system"
  exit 1
fi
chgrp $newgroup /etc/cron.allow

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

Ansible playbook

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Check that the crontab group is defined
  getent:
    database: group
    key: crontab
  ignore_errors: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - file_groupowner_cron_allow_newgroup is undefined
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set the file_groupowner_cron_allow_newgroup variable if crontab found
  set_fact:
    file_groupowner_cron_allow_newgroup: crontab
  when:
  - '"linux-base" in ansible_facts.packages'
  - ansible_facts.getent_group["crontab"] is defined
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /etc/cron.allow
  stat:
    path: /etc/cron.allow
  register: file_exists
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner on /etc/cron.allow
  file:
    path: /etc/cron.allow
    group: '{{ file_groupowner_cron_allow_newgroup }}'
  when:
  - '"linux-base" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed