SV-205921r991589: Windows Server 2019 session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption. | Microsoft Windows Server 2019 STIG SCAP Benchmark

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Assessment Title

Rule Text

Windows Server 2019 session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption.

Description

Discussion Text

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.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000366SV-103393V-93305

References

DPMS Target Microsoft Windows Server 2019 DISA DPMS Target Microsoft Windows Server 2019 2907

Checks

DISA STIG (Manual Reference)

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)

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

# Windows PowerShell
# Reconstructed from oval:mil.disa.stig.windows2019:def:205921
# Windows Server 2019 session security for NTLM SSP-based clients must be configured to require NTLMv2 session security and 128-bit encryption.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# The system is configured to meet the minimum session security requirement for NTLM SSP based clients.
# registry_object (registry_test)
function test_1 {
  return (((@{String='reg_sz';ExpandString='reg_expand_sz';Binary='reg_binary';DWord='reg_dword';MultiString='reg_multi_sz';QWord='reg_qword';None='reg_none'}[(Get-Item -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0').GetValueKind('NTLMMinClientSec').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinClientSec' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'NTLMMinClientSec') -eq 537395200))
}

if (test_1) {
  Write-Output "PASS"
} else {
  Write-Output "FAIL"
}

Assessment Script Powered by AISyntax-verified

A standalone PowerShell script to assess this control automatically. Review before running it in your environment.

Syntax-checked as valid PowerShell. Not executed here — running it for real needs the actual ms_windows_server_2019 target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windows2019:def:205921
if ((Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0" -Name "NTLMMinClientSec" -ErrorAction SilentlyContinue).NTLMMinClientSec -eq 537395200) { Write-Output "PASS"; Exit 0 } else { Write-Output "FAIL"; Exit 1 }

Remediation

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).