SV-226300r794591: The service principal name (SPN) target name validation level must be turned off. | Microsoft Windows Server 2012/2012 R2 Domain Controller STIG SCAP Benchmark

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Assessment Title

Rule Text

The service principal name (SPN) target name validation level must be turned off.

Description

Discussion Text

If a service principle name (SPN) is provided by the client, it is validated against the server's list of SPNs. Implementation may disrupt file and print sharing capabilities.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366CCE-24502-7SV-53175V-21950

References

DPMS Target Microsoft Windows Server 2012-2012 R2 DC DISA DPMS Target Microsoft Windows Server 2012-2012 R2 DC 4217

Checks

OVAL

oval:mil.disa.fso.windows:var:456400 ← xccdf_mil.disa.stig_value_microsoft_network_server_server_spn_target_name_validation_level_var

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\Services\LanmanServer\Parameters\

Value Name: SmbServerNameHardeningLevel

Type: REG_DWORD
Value: 0

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:4564
# The service principal name (SPN) target name validation level must be turned off.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'Microsoft network server: Server SPN target name validation level' is set to 'Off'
# 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\Services\LanManServer\Parameters').GetValueKind('SMBServerNameHardeningLevel').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer\Parameters' -Name 'SMBServerNameHardeningLevel' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'SMBServerNameHardeningLevel') -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:4564
$registryPath = "HKLM:\System\CurrentControlSet\Services\LanManServer\Parameters"
$registryValueName = "SMBServerNameHardeningLevel"
if (Test-Path $registryPath) {
    $registryValue = Get-ItemProperty -Path $registryPath -Name $registryValueName -ErrorAction SilentlyContinue
    if ($registryValue -and $registryValue.$registryValueName -eq 0) {
        Write-Output "PASS"
        exit 0
    }
}
Write-Output "FAIL"
exit 1

Remediation

Configure the policy value for Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> Security Options -> "Microsoft network server: Server SPN target name validation level" to "Off".