Insecure logons to an SMB server must be disabled. GROUP ID: V-220802RULE ID: SV-220802r991589 Insecure guest logons allow unauthenticated access to shared folders. Shared resources on a system must require authentication to establish proper access.
Solution
Configure the policy value for Computer Configuration >> Administrative Templates >> Network >> Lanman Workstation >> 'Enable insecure guest logons' to 'Disabled'.