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

STIG ID: WN19-CC-000070 |  SRG: SRG-OS-000480-GPOS-00227 |  Severity: medium |  CCI:  | Vulnerability Id: V-205861

Vulnerability Discussion

Insecure guest logons allow unauthenticated access to shared folders. Shared resources on a system must require authentication to establish proper access.

Check

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

Fix

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)