CISC-ND-001150 The Cisco router must be configured to authenticate Network Time Protocol (NTP) sources using authentication that is cryptographically based.
All changes in this version
Maps to IA-3(1) via CCI-001967
Title
The Cisco router must be configured to authenticate Network Time Protocol (NTP) sources using authentication that is cryptographically based.
Control
Review the Cisco router configuration to verify that it is compliant with this requirement as shown in the configuration example below. ntp authentication-key 1 hmac-sha2-256 xxxxxx ntp authenticate ntp trusted-key 1 ntp server x.x.x.x key 1 ntp server y.y.y.y key 1 If the Cisco router is not configured to authenticate NTP sources using authentication that is cryptographically based, this is a finding.
Discussion
If Network Time Protocol is not authenticated, an attacker can introduce a rogue NTP server. This rogue server can then be used to send incorrect time information to network devices, which will make log timestamps inaccurate and affect scheduled actions. NTP authentication is used to prevent this tampering by authenticating the time source.
Related controls
CCI-001967
Fix
Configure the Cisco router to authenticate NTP sources using authentication that is cryptographically based as shown in the example below. R2(config)#ntp authenticate R2(config)#ntp authentication-key 1 hmac-sha2-256 xxxxxxx R2(config)#ntp trusted-key 1 R2(config)#ntp server x.x.x.x key 1 R2(config)#ntp server y.y.y.y key 1