SV-205684r958478: Windows Server 2019 must have the Server Message Block (SMB) v1 protocol disabled on the SMB client. | Microsoft Windows Server 2019 STIG SCAP Benchmark

Loading benchmark…

Assessment Title

Rule Text

Windows Server 2019 must have the Server Message Block (SMB) v1 protocol disabled on the SMB client.

Description

Discussion Text

SMBv1 is a legacy protocol that uses the MD5 algorithm as part of SMB. MD5 is known to be vulnerable to a number of attacks such as collision and preimage attacks as well as not being FIPS compliant.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000381V-93395SV-103481

References

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

Checks

DISA STIG (Manual Reference)

Different methods are available to disable SMBv1 on Windows Server 2019, if WN19-00-000380 is configured, this is NA.

If the following registry value is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SYSTEM\CurrentControlSet\Services\mrxsmb10\

Value Name: Start

Type: REG_DWORD
Value: 0x00000004 (4)

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:205684
# Windows Server 2019 must have the Server Message Block (SMB) v1 protocol disabled on the SMB client.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'SMB 1.0/CIFS File Sharing Support' feature is not installed
# wmi57_object (wmi57_test)
function test_1 {
  return (((Get-CimInstance -Namespace 'root\cimv2' -Query 'SELECT installstate FROM win32_optionalfeature WHERE name = ''SMB1Protocol''' | Select-Object -First 1) | Select-Object -ExpandProperty 'installstate') -eq '2')
}
# Verifies 'Configure SMBv1 client driver' is set to 'Enabled' with 'Disable driver (recommended)' selected for 'Configure MrxSmb10 driver'
# 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\Services\mrxsmb10').GetValueKind('Start').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\mrxsmb10' -Name 'Start' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'Start') -eq 4))
}

if ((test_1 -or test_2)) {
  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:mil.disa.stig.windows2019:def:205684

$smb1FeatureState = Get-CimInstance -ClassName Win32_OptionalFeature -Filter "Name = 'SMB1Protocol'" | Select-Object -ExpandProperty InstallState
if ($smb1FeatureState -eq 2 -or (Test-Path -Path "HKLM:\SYSTEM\CurrentControlSet\Services\mrxsmb10" -and (Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\mrxsmb10" -Name Start).Start -eq 4)) {
    Write-Output "PASS"
    exit 0
} else {
    Write-Output "FAIL"
    exit 1
}

Remediation

Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "Configure SMBv1 client driver" to "Enabled" with "Disable driver (recommended)" selected for "Configure MrxSmb10 driver".

The system must be restarted for the changes to take effect.

This policy setting requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.