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V-215843

CAT II (Medium)

The Cisco router must be configured to authenticate Network Time Protocol (NTP) sources using authentication that is cryptographically based.

Rule ID

SV-215843r1050862_rule

STIG

Cisco IOS XE Router NDM Security Technical Implementation Guide

Version

V3R7

CCIs

CCI-001967

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.

Check Content

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.

Fix Text

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