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cis-ubuntu1804-v220-4-1-2

DevOps & Security
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Ensure permissions on /etc/crontab are configured

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_18.04_LTS_Benchmark_v2.2.0/cis-ubuntu1804-v220-4-1-2/SKILL.md

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CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 4.1.2

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.

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.

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 -c "%a %U %G" /etc/crontab

Expected Result

600 root root

OR more restrictive.

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

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

References

  1. NIST SP 800-53 Rev. 5: AC-3, MP-2

CIS Controls

v8 - 3.3 Configure Data Access Control Lists - Configure data access control lists based on a user's need to know. Apply data access control lists, also known as access permissions, to local and remote file systems, databases, and applications.

v7 - 14.6 Protect Information through Access Control Lists - Protect all information stored on systems with file system, network share, claims, application, or database specific access control lists.

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Assessment Status

Automated