Windows Server 2025 session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-278227 | SRG-OS-000480-GPOS-00227 | WN25-SO-000330 | SV-278227r1181387_rule | 2026-02-20 | 1 |
Description
Microsoft has implemented a variety of security support providers for use with Remote Procedure Call (RPC) sessions. All of the options must be enabled to ensure the maximum security level.
ℹ️ Check
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: NTLMMinClientSec
Value Type: REG_DWORD
Value: 0x20080000 (537395200)
✔️ Fix
Configure the policy value for Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> Network security: Minimum session security for NTLM SSP based (including secure RPC) clients to "Require NTLMv2 session security" and "Require 128-bit encryption" (all options selected).