Cisco IOS XE Router NDM STIG Version Comparison

There are 2 differences between versions v3 r2 (Oct. 24, 2024) (the "left" version) and v3 r4 (April 2, 2025) (the "right" version).

Check CISC-ND-001150 was changed between these two versions. Green, underlined text was added, red, struck-out text was removed.

The regular view of the left check and right check may be easier to read.

Title

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

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 md5 121B0A151012 7 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.

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 md5 hmac-sha2-256 xxxxxx R2(config)#ntp 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