Details

Sets a NTP server for which authentication is enabled in order to receive time information

Rationale:

When authentication is not enabled, attackers can disguise as NTP servers and broadcast wrong time and it will be difficult to correlate events upon an incident. In some other cases, attackers can perform NTP DDoS attacks such as NTP Amplification. The trusted NTP server will be authenticated through the NTP authentication key.

Solution

Step 1: Acquire the authentication key ID , the IP address of the NTP server and the interface used by the appliance to communicate with the NTP server.

Step 2: Run the following to configure the trusted NTP server

hostname(config)# ntp server key source

Default Value:

Disabled by default

Supportive Information

The following resource is also helpful.

• https://workbench.cisecurity.org/files/3294

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Cisco.

References

• 800-53|CM-2
• CSCv6|6.1
• CSCv7|11.1

Source

• Tenable.com/audits