2.2.1.2 Ensure ntp is configured - restrict -4

Information

ntp is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on NTP can be found at http://www.ntp.org. ntp can be configured to be a client and/or a server.

This recommendation only applies if ntp is in use on the system.

Rationale:

If ntp is in use on the system proper configuration is vital to ensuring time synchronization is working properly.

Solution

Add or edit restrict lines in /etc/ntp.conf to match the following:

restrict -4 default kod limited nomodify notrap nopeer noquery
restrict -6 default kod limited nomodify notrap nopeer noquery

Add or edit server or pool lines to /etc/ntp.conf as appropriate:

server <remote-server>

Add or edit the NTPD_OPTIONS in /etc/sysconfig/ntp to include '-u ntp:ntp':

NTPD_OPTIONS='-u ntp:ntp'

See Also

https://workbench.cisecurity.org/files/3738

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-7, 800-53|AU-8, CSCv7|6.1

Plugin: Unix

Control ID: 709660fe9e5464b5ef6f6a6fa886fd4640e2c0cbace6426a99baa8a3a5476160