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The system will be configured to meet the minimum session security requirement for NTLM SSP based clients.


Overview

Finding ID Version Rule ID IA Controls Severity
V-3382 3.076 SV-32341r1_rule Medium
Description
Windows has implemented a variety of security support providers for use with RPC sessions. In a homogenous Windows environment, all of the options should be enabled and testing should be performed in a heterogeneous environment to determine the maximum-security level that provides reliable functionality.
STIG Date
Windows Server 2008 R2 Member Server Security Technical Implementation Guide 2019-06-18

Details

Check Text ( C-32747r1_chk )
Analyze the system using the Security Configuration and Analysis snap-in.
Expand the Security Configuration and Analysis tree view.
Navigate to Local Policies -> Security Options.

If the value for “Network security: Minimum session security for NTLM SSP based (including secure RPC) clients” is not set to “Require NTLMv2 session security” and “Require 128-bit encryption”, then this is a finding.

The policy referenced configures the following registry value:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \System\CurrentControlSet\Control\Lsa\MSV1_0\

Value Name: NTLMMinClientSec

Value Type: REG_DWORD
Value: 0x20080000 (537395200)


Warnings:
Microsoft warns that setting these may prevent the client from communicating with legacy servers that do not support them.

“Require NTLMv2 session security” will prevent authentication, if the “Network security: LAN Manager Authentication level” is set to permit NTLM or LM authentication.

Documentable Explanation: If these settings need to be modified in a mixed Windows environment, the changes should be documented with the IAO.

Fix Text (F-28826r1_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”, ”Require 128-bit encryption” (all options selected).