SV-15981r1: The system is not configured to meet the minimum requirement for session security for NTLM SSP based Servers. | Windows Vista Security Technical Implementation Guide

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Assessment Title

Rule Text

The system is not configured to meet the minimum requirement for session security for NTLM SSP based Servers.

Description

Discussion Text

Microsoft 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.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366CCE-4213-5

Additional Details

Potential Impacts

Microsoft warns that setting these may prevent the server from communicating with legacy clients 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.

Responsibility

Information Assurance Officer

References

DPMS Target Windows Vista DISA DPMS Target Windows Vista 1029

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.fso.windows:def:480
# The system is not configured to meet the minimum requirement for session security for NTLM SSP based Servers.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# registry_object (registry_test)
function test_1 {
  return ($null -ne (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec'))
}
# registry_object (registry_test)
function test_2 {
  return ((@{String='reg_sz';ExpandString='reg_expand_sz';Binary='reg_binary';DWord='reg_dword';MultiString='reg_multi_sz';QWord='reg_qword';None='reg_none'}[(Get-Item -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0').GetValueKind('NTLMMinServerSec').ToString()]) -eq 'reg_dword')
}
# registry_object (registry_test)
function test_3 {
  return (-not ($null -ne (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec')))
}
# registry_object (registry_test)
function test_4 {
  return (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'NTLMMinServerSec') -eq 537395200)
}
# registry_object (registry_test)
function test_5 {
  return (-not ($null -ne (Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec')))
}

if ((test_1 -and (test_2 -or test_3) -and (test_4 -or test_5))) {
  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 windows_vista target this check assesses.

# OVAL Definition: oval:mil.disa.fso.windows:def:480
$compliant = (Get-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec' -ErrorAction SilentlyContinue).NTLMMinServerSec -ge 134217728 -and (Get-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'NTLMMinServerSec' -ErrorAction SilentlyContinue).NTLMMinServerSec -ne 0; if ($compliant) {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) servers” to “Require NTLMv2 session security”, ”Require 128-bit encryption (all options selected).