Session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption.

From Windows Server 2016 Security Technical Implementation Guide

Associated with: CCI-000366

SV-88359r1_rule Session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption.

Vulnerability discussion

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.

Check content

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 text

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).

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