cis-ubuntu2004-v300-2-3-3-3

DevOps & Security

Ensure chrony is enabled and running

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_20.04_LTS_Benchmark_v3.0.0/cis-ubuntu2004-v300-2-3-3-3/SKILL.md

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Ensure chrony is enabled and running

Profile

Level 1 - Server
Level 1 - Workstation

Description

chrony is a daemon which implements the Network Time Protocol (NTP) and is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate.

chrony can be configured to be a client and/or a server.

More information on chrony can be found at: http://chrony.tuxfamily.org/.

Note:

If systemd-timesyncd is being used, chrony should be removed and this section skipped
Only one time synchronization method should be in use on the system

Audit

IF - chrony is in use on the system, run the following commands:

Run the following command to verify chrony is enabled:

Command Line

# systemctl is-enabled chrony.service

Output:

enabled

Run the following command to verify chrony is running:

# systemctl is-active chrony.service

Output:

active

Remediation

IF - chrony is in use on the system, run the following commands:

Run the following command to unmask chrony.service:

Command Line

# systemctl unmask chrony.service

Run the following command to enable and start chrony.service:

# systemctl --now enable chrony.service

- OR -

If another time synchronization service is in use on the system, run the following command to remove chrony from the system:

# apt purge chrony
# apt autoremove chrony

References

NIST SP 800-53 Rev. 5: AU-8

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	8.4 Standardize Time SynchronizationStandardize time synchronization. Configure at least two synchronized time sources across enterprise assets, where supported.		●	●
v7	6.1 Utilize Three Synchronized Time SourcesUse at least three synchronized time sources from which all servers and network devices retrieve time information on a regular basis so that timestamps in logs are consistent.		●	●

MITRE ATT&CK Mappings

Techniques / Sub-techniques	Tactics	Mitigations
T1070, T1070.002, T1562, T1562.001	TA0002	M1022