The service principal name (SPN) target name validation level must be configured to Accept if provided by client.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-63735	WN10-SO-000135	SV-78225r1_rule		Medium

Description
If a service principle name (SPN) is provided by the client, it is validated against the server's list of SPNs, aiding in the prevention of spoofing.

STIG	Date
Windows 10 Security Technical Implementation Guide	2016-06-24

Details

Check Text ( C-64485r1_chk )
If the following registry value does not exist or is not configured as specified, this is a finding: Registry Hive: HKEY_LOCAL_MACHINE Registry Path: \SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\ Value Name: SmbServerNameHardeningLevel Value Type: REG_DWORD Value: 1

Fix Text (F-69663r1_fix)
Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Microsoft network server: Server SPN target name validation level" to "Accept if provided by client".