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:4588
# NTLM must be prevented from falling back to a Null session.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
# Verifies 'Network security: Allow LocalSystem NULL session fallback' is set to 'Disabled'
# 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('allownullsessionfallback').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa\MSV1_0' -Name 'allownullsessionfallback' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'allownullsessionfallback') -eq 0))
}
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_2012_and_2012_r2_dc target this check assesses.
# OVAL Definition: oval:mil.disa.fso.windows:def:4588
$registryPath = "HKLM:\System\CurrentControlSet\Control\Lsa\MSV1_0"
$regValueName = "allownullsessionfallback"
if (-not (Test-Path $registryPath)) { exit 0 }
$regValue = Get-ItemProperty -Path $registryPath -Name $regValueName -ErrorAction SilentlyContinue
if ($regValue -eq $null -or $regValue.$regValueName -ne 0) { exit 1 }
exit 0