Cisco IOS Router NDM STIG Version Comparison

There are 2 differences between versions v3 r4 (April 2, 2025) (the "left" version) and v3 r6 (Jan. 5, 2026) (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 with FIPS-compliant algorithms. that is cryptographically based.

Check Content

Review the Cisco router configuration to verify that it is compliant authenticates NTP sources using authentication with this requirement FIPS-compliant algorithms as shown in the configuration example below. ntp below: ntp authentication-key 1 md5 xxxxxx ntp 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 1 NOTE: Cisco IOS is limited to MD5 for NTP authentication, and incurs a permanent finding as it is not FIPS compliant. MD5 partially reduces the risk but cannot fully mitigate it. If the Cisco router is not configured to authenticate NTP sources using authentication with FIPS-compliant algorithms, that is cryptographically based, this is a finding.

Discussion

If NTP 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 with FIPS-compliant algorithms that is cryptographically based as shown in the example below. R2(config)#ntp below: R2(config)#ntp authenticate R2(config)#ntp authentication-key 1 md5 xxxxxx 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