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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-3666	WN08-SO-000070	SV-48120r1_rule		Medium

Description
Microsoft has implemented a variety of security support providers for use with RPC sessions. All of the options must be enabled to ensure the maximum security level.

STIG	Date
Windows 8/8.1 Security Technical Implementation Guide	2017-05-17

Details

Check Text ( C-44846r1_chk )
Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.) 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) servers" is not set to "Require NTLMv2 session security" and "Require 128-bit encryption", 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: NTLMMinServerSec Value Type: REG_DWORD Value: 0x20080000 (537395200) "Require NTLMv2 session security" will prevent authentication if "Network security: LAN Manager Authentication level" is set to permit NTLM or LM authentication.

Check Text ( C-44846r1_chk )

Analyze the system using the Security Configuration and Analysis snap-in. (See "Performing Analysis with the Security Configuration and Analysis Snap-in" in the STIG Overview document.)
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) servers" is not set to "Require NTLMv2 session security" and "Require 128-bit encryption", 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: NTLMMinServerSec

Value Type: REG_DWORD
Value: 0x20080000 (537395200)

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

Fix Text (F-41257r1_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) servers" to "Require NTLMv2 session security" and "Require 128-bit encryption" (all options selected).