The system clock must be synchronized continuously, or at least daily.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22290	GEN000241	SV-26292r1_rule	ECSC-1	Medium

Description
A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. Internal system clocks tend to drift and require periodic resynchronization to ensure their accuracy. Software, such as ntpd, can be used to continuously synchronize the system clock with authoritative sources. Alternatively, the system may be synchronized periodically, with a maximum of one day between synchronizations. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.

Description

A synchronized system clock is critical for the enforcement of time-based policies and the correlation of logs and audit records with other systems. Internal system clocks tend to drift and require periodic resynchronization to ensure their accuracy. Software, such as ntpd, can be used to continuously synchronize the system clock with authoritative sources. Alternatively, the system may be synchronized periodically, with a maximum of one day between synchronizations. If the system is completely isolated (i.e., it has no connections to networks or other systems), time synchronization is not required as no correlation of events or operation of time-dependent protocols between systems will be necessary. If the system is completely isolated, this requirement is not applicable.

STIG	Date
Red Hat Enterprise Linux 5 Security Technical Implementation Guide	2013-04-10

Details

Check Text ( C-27388r1_chk )
Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/* for the presence of an "ntpd -qg" job to run at least daily, which should have asterisks (*) in columns 3, 4, and 5. Check the daily cron directory (/etc/cron.daily) for any script running "ntpd -qg". Check for a running NTP daemon. # ps ax \| grep ntpd If none of the above checks are successful, this is a finding.

Check Text ( C-27388r1_chk )

Check the root crontab (crontab -l) and the global crontabs in /etc/crontab, /etc/cron.d/* for the presence of an "ntpd -qg" job to run at least daily, which should have asterisks (*) in columns 3, 4, and 5.

Check the daily cron directory (/etc/cron.daily) for any script running "ntpd -qg".

Check for a running NTP daemon.
# ps ax | grep ntpd

If none of the above checks are successful, this is a finding.

Fix Text (F-23444r1_fix)
Enable the NTP daemon for continuous synchronization. # service ntpd start ; chkconfig ntpd on OR Add a daily or more frequent cronjob to perform synchronization using ntpdate.