Windows Server 2019 insecure logons to an SMB server must be disabled.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-205861WN19-CC-000070SV-205861r991589_ruleCCI-000366medium
Description
Insecure guest logons allow unauthenticated access to shared folders. Shared resources on a system must require authentication to establish proper access.
STIGDate
Microsoft Windows Server 2019 Security Technical Implementation Guide2025-05-23

Details

Check Text (C-205861r991589_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: \SOFTWARE\Policies\Microsoft\Windows\LanmanWorkstation\ Value Name: AllowInsecureGuestAuth Type: REG_DWORD Value: 0x00000000 (0)

Fix Text (F-6126r355946_fix)

Configure the policy value for Computer Configuration >> Administrative Templates >> Network >> Lanman Workstation >> "Enable insecure guest logons" to "Disabled".