Cis Ubuntu1804 V220 2 1 4 4

2.1.4.4 Ensure ntp is enabled and running (Automated)

Profile

• Level 1 - Server
• Level 1 - Workstation

Description

ntp is a daemon for synchronizing the system clock across the network.

Rationale

ntp needs to be enabled and running in order to synchronize the system to a timeserver.

Time synchronization is important to support time sensitive security mechanisms and to ensure log files have consistent time records across the enterprise to aid in forensic investigations.

Audit Procedure

Command Line

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

Run the following command to verify that the ntp service is enabled:

# systemctl is-enabled ntp.service
enabled

Run the following command to verify that the ntp service is active:

# systemctl is-active ntp.service
active

Expected Result

• systemctl is-enabled ntp.service returns enabled
• systemctl is-active ntp.service returns active

Remediation

Command Line

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

Run the following command to unmask ntp.service:

# systemctl unmask ntp.service

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

# systemctl --now enable ntp.service

OR

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

# apt purge ntp

References

1. NIST SP 800-53 Rev. 5: AU-7, AU-8

CIS Controls

• v8: 8.4 - Standardize Time Synchronization
• v7: 6.1 - Utilize Three Synchronized Time Sources