Windows Server 2022 must prevent NTLM from falling back to a Null session.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-254471 | WN22-SO-000270 | SV-254471r991589_rule | Medium |
| Description |
| NTLM sessions that are allowed to fall back to Null (unauthenticated) sessions may gain unauthorized access. |
| STIG | Date |
| Microsoft Windows Server 2022 Security Technical Implementation Guide | 2025-01-14 |
Details
| Check Text (C-57956r849227_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\Control\LSA\MSV1_0\ Value Name: allownullsessionfallback Type: REG_DWORD Value: 0x00000000 (0) |
| Fix Text (F-57907r849228_fix) |
| Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> Network security: Allow LocalSystem NULL session fallback to "Disabled". |