STIGQter: STIG Summary: Canonical Ubuntu 18.04 LTS Security Technical Implementation Guide Version: 2 Release: 3 Benchmark Date: 23 Apr 2021:

The Ubuntu operating system must, for networked systems, compare internal information system clocks at least every 24 hours with a server which is synchronized to one of the redundant United States Naval Observatory (USNO) time servers, or a time server designated for the appropriate DoD network (NIPRNet/SIPRNet), and/or the Global Positioning System (GPS).

DISA Rule

SV-219331r610963_rule

Vulnerability Number

V-219331

Group Title

SRG-OS-000355-GPOS-00143

Rule Version

UBTU-18-010501

Severity

CAT II

CCI(s)

• CCI-001891 - The information system compares internal information system clocks on an organization-defined frequency with an organization-defined authoritative time source.

Weight

10

Fix Recommendation

If the system is not networked this requirement is Not Applicable.

To configure the system clock to compare the system clock at least every 24 hours to the authoritative time source, edit the "/etc/chrony/chrony.conf" file. Add or correct the following lines, by replacing "[source]" in the following line with an authoritative DoD time source.

server [source] iburst maxpoll = 17

If the "chrony" service was running and the value of "maxpoll" or "server" was updated then the service must be restarted using the following command:

# sudo systemctl restart chrony.service

Check Contents

If the system is not networked this requirement is Not Applicable.

The system clock must be configured to compare the system clock at least every 24 hours to the authoritative time source.

Check the value of "maxpoll" in the "/etc/chrony/chrony.conf" file with the following command:

# sudo grep maxpoll /etc/chrony/chrony.conf
server tick.usno.navy.mil iburst maxpoll 17

If "maxpoll" is not set to "17" or does not exist, this is a finding.

Verify that the "chrony.conf" file is configured to an authoritative DoD time source by running the following command:

# grep -i server /etc/chrony/chrony.conf
server tick.usno.navy.mil iburst maxpoll 17
server tock.usno.navy.mil iburst maxpoll 17
server ntp2.usno.navy.mil iburst maxpoll 17

If the parameter "server" is not set, is not set to an authoritative DoD time source, or is commented out, this is a finding.

Vulnerability Number

V-219331

Documentable

False

Rule Version

UBTU-18-010501

Severity Override Guidance

If the system is not networked this requirement is Not Applicable.

The system clock must be configured to compare the system clock at least every 24 hours to the authoritative time source.

Check the value of "maxpoll" in the "/etc/chrony/chrony.conf" file with the following command:

# sudo grep maxpoll /etc/chrony/chrony.conf
server tick.usno.navy.mil iburst maxpoll 17

If "maxpoll" is not set to "17" or does not exist, this is a finding.

Verify that the "chrony.conf" file is configured to an authoritative DoD time source by running the following command:

# grep -i server /etc/chrony/chrony.conf
server tick.usno.navy.mil iburst maxpoll 17
server tock.usno.navy.mil iburst maxpoll 17
server ntp2.usno.navy.mil iburst maxpoll 17

If the parameter "server" is not set, is not set to an authoritative DoD time source, or is commented out, this is a finding.

Check Content Reference

M

Target Key

4055

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