SV-225045r991589: Anonymous enumeration of Security Account Manager (SAM) accounts must not be allowed. | Microsoft Windows Server 2016 STIG SCAP Benchmark

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Assessment Title

Rule Text

Anonymous enumeration of Security Account Manager (SAM) accounts must not be allowed.

Description

Discussion Text

Anonymous enumeration of SAM accounts allows anonymous logon users (null session connections) to list all accounts names, thus providing a list of potential points to attack the system.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366SV-88331V-73667

References

DPMS Target Microsoft Windows Server 2016 DISA DPMS Target Microsoft Windows Server 2016 4205

Checks

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\Control\Lsa\

Value Name: RestrictAnonymousSAM

Value Type: REG_DWORD
Value: 0x00000001 (1)

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.windows:def:1205
# Anonymous enumeration of Security Account Manager (SAM) accounts must not be allowed.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'Network access: Do not allow anonymous enumeration of SAM accounts' is set to 'Enabled'
# 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').GetValueKind('RestrictAnonymousSAM').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa' -Name 'RestrictAnonymousSAM' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'RestrictAnonymousSAM') -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 ms_windows_server_2016 target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windows:def:1205
$regPath = "HKLM:\System\CurrentControlSet\Control\Lsa"
$regKey = "RestrictAnonymousSAM"
if (Test-Path $regPath) {
    $regValue = (Get-ItemProperty -Path $regPath -Name $regKey -ErrorAction SilentlyContinue).$regKey
    if ($regValue -ne $null -and $regValue -eq 1) {
        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 >> "Network access: Do not allow anonymous enumeration of SAM accounts" to "Enabled".