SV-25273r2: The service principal name (SPN) target name validation level must be configured to Accept if provided by client. | Windows 7 Security Technical Implementation Guide

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Assessment Title

Rule Text

The service principal name (SPN) target name validation level must be configured to Accept if provided by client.

Description

Discussion Text

If a service principle name (SPN) is provided by the client, it is validated against the server's list of SPNs, aiding in the prevention of spoofing.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366CCE-8503-5

Additional Details

Responsibility

System Administrator

References

DPMS Target Windows 7 DISA DPMS Target Windows 7 1712

Checks

OVAL

oval:mil.disa.fso.windows:var:374600 ← xccdf_mil.disa.stig_value_microsoft_network_server_server_spn_target_name_validation_level_var

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:3746
# The service principal name (SPN) target name validation level must be configured to Accept if provided by client.
# 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 'Accept if provided by client'
# 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 1))
}

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 windows_7 target this check assesses.

# OVAL Definition: oval:mil.disa.fso.windows:def:3746
$compliant = (Get-ItemProperty -Path "HKLM:\System\CurrentControlSet\Services\LanManServer\Parameters" -Name "SMBServerNameHardeningLevel" -ErrorAction SilentlyContinue).SMBServerNameHardeningLevel -eq 1
if ($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 >> "Microsoft network server: Server SPN target name validation level" to "Accept if provided by client".