cis-ubuntu1604-v200-2-1-1-1

name	cis-ubuntu1604-v200-2-1-1-1
description	Ensure time synchronization is in use
category	cis-networking
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","services"]
cis_id	2.1.1.1
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

2.1.1.1 Ensure time synchronization is in use (Automated)

Description

System time should be synchronized between all systems in an environment. This is typically done by establishing an authoritative time server or set of servers and having all systems synchronize their clocks to them.

Notes:

• If access to a physical host's clock is available and configured according to site policy, this section can be skipped
• Only one time synchronization method should be in use on the system
• Only the section related to the time synchronization method in use on the system should be followed, all other time synchronization recommendations should be skipped
• If access to a physical host's clock is available and configured according to site policy, systemd-timesyncd should be stopped and masked

Rationale

Time synchronization is important to support time sensitive security mechanisms like Kerberos and also ensures log files have consistent time records across the enterprise, which aids in forensic investigations.

Audit Procedure

Command Line

On physical systems or virtual systems where host based time synchronization is not available verify that timesyncd, chrony, or NTP is installed. Use one of the following commands to determine the needed information:

If systemd-timesyncd is used:

systemctl is-enabled systemd-timesyncd

If chrony is used:

dpkg -s chrony

If ntp is used:

dpkg -s ntp

On virtual systems where host based time synchronization is available consult your virtualization software documentation and verify that host based synchronization is in use.

Expected Result

One of the time synchronization services (systemd-timesyncd, chrony, or ntp) should be installed and enabled.

Remediation

Command Line

On systems where host based time synchronization is not available, configure systemd-timesyncd. If "full featured" and/or encrypted time synchronization is required, install chrony or NTP.

To install chrony:

apt install chrony

To install ntp:

apt install ntp

On virtual systems where host based time synchronization is available consult your virtualization software documentation and setup host based synchronization.

Default Value

Time synchronization is not configured by default.

References

1. CIS Controls v7 - 6.1 Utilize Three Synchronized Time Sources