2.2.1.4 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 nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

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

server <remote-server>

Configure ntp to run as the ntp user by adding or editing the /etc/init.d/ntp file:

RUNASUSER=ntp

See Also

https://workbench.cisecurity.org/files/2971

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-8, CSCv6|6.1, CSCv7|6.1

Plugin: Unix

Control ID: 363e6ee7c88106a0ca00334dee344d14aad48725ece4590c863e6a5d33b772c6