cis-ubuntu1604-v200-5-1-2

name	cis-ubuntu1604-v200-5-1-2
description	Ensure permissions on /etc/crontab are configured
category	cis-iam
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","access-control"]
cis_id	5.1.2
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - 5.1.2

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Description

The /etc/crontab file is used by cron to control its own jobs. The commands in this item make sure that root is the user and group owner of the file and that only the owner can access the file.

Note: Other methods, such as systemd timers, exist for scheduling jobs. If another method is used, cron should be removed, and the alternate method should be secured in accordance with local site policy.

Rationale

This file contains information on what system jobs are run by cron. Write access to these files could provide unprivileged users with the ability to elevate their privileges. Read access to these files could provide users with the ability to gain insight on system jobs that run on the system and could provide them a way to gain unauthorized privileged access.

Impact

None.

Audit Procedure

Command Line

Run the following command and verify Uid and Gid are both 0/root and Access does not grant permissions to group or other:

stat /etc/crontab

Expected Result

Access: (0600/-rw-------)  Uid: (    0/    root)  Gid: (    0/    root)

Remediation

Command Line

Run the following commands to set ownership and permissions on /etc/crontab:

chown root:root /etc/crontab
chmod og-rwx /etc/crontab

Default Value

By default, /etc/crontab is owned by root:root with permissions 0644.

References

None.

CIS Controls

Controls Version	Control
v7	14.6 Protect Information through Access Control Lists

Assessment Status

Automated