The system clock must be synchronized continuously.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-000366

SV-63143r4_rule The system clock must be synchronized continuously.

Vulnerability discussion

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.

Check content

Check to see if ntp is running in continuous mode. # ps -ax | grep ntp If the process is found, then check the ntp.conf file for the maxpoll option setting. # grep maxpoll /etc/ntp.conf If the option is set to 17 or is not set, this is a finding.

Fix text

Enable the NTP daemon for continuous synchronization. # service ntpd start ; chkconfig ntpd on Edit the "/etc/ntp.conf" file and add or update an entry to define "maxpoll" to "10".

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