The Edge SWG must authenticate Network Time Protocol sources using authentication that is cryptographically based.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-279269	SRG-APP-000395-NDM-000347	SYME-ND-000720	SV-279269r1170698_rule	2025-12-18	1

Description
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. Satisfies: SRG-APP-000395-NDM-000347, SRG-APP-000920-NDM-000320, SRG-APP-000925-NDM-000330

Description

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. Satisfies: SRG-APP-000395-NDM-000347, SRG-APP-000920-NDM-000320, SRG-APP-000925-NDM-000330

ℹ️ Check
1. Log in to the Edge SWG SSH CLI. 2. Enter "enable" and "configure terminal". 3. Enter "show ntp". If NTP is not enabled, this is a finding. If there are not two NTP servers in use, this is a finding. If the two NTP servers are not using SHA1 preshared keys for authentication, this is a finding.

✔️ Fix
1. Log in to the Edge SWG SSH CLI. 2. Enter "enable" and "configure terminal". 3. Enter "ntp enable". 4. Enter "ntp server <NTP SERVER IP/HOSTNAME> <KEY ID> sha1". Note: The key ID must be a number and match the NTP server. 5. When prompted with "key:", enter the hexadecimal SHA preshared key. 6. Repeat these steps for the site's second NTP server.