SV-225013r958726: Remote calls to the Security Account Manager (SAM) must be restricted to Administrators. | Microsoft Windows Server 2016 STIG SCAP Benchmark

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Assessment Title

Rule Text

Remote calls to the Security Account Manager (SAM) must be restricted to Administrators.

Description

Discussion Text

The Windows Security Account Manager (SAM) stores users' passwords. Restricting Remote Procedure Call (RPC) connections to the SAM to Administrators helps protect those credentials.

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

IA Controls

NIST SP 800-53

Not mappedCCI-002235SV-88341V-73677

References

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

Checks

DISA STIG (Manual Reference)

This applies to member servers and standalone or nondomain-joined systems. It is NA for domain controllers.

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: RestrictRemoteSAM

Value Type: REG_SZ
Value: O:BAG:BAD:(A;;RC;;;BA)

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:1210
# Remote calls to the Security Account Manager (SAM) must be restricted to Administrators.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# System is a DC
# wmi57_object (wmi57_test)
function test_1 {
  return ((((Get-CimInstance -Namespace 'root\cimv2' -Query 'SELECT DomainRole FROM win32_computersystem' | Select-Object -First 1) | Select-Object -ExpandProperty 'DomainRole') -eq '5') -or (((Get-CimInstance -Namespace 'root\cimv2' -Query 'SELECT DomainRole FROM win32_computersystem' | Select-Object -First 1) | Select-Object -ExpandProperty 'DomainRole') -eq '4'))
}
# Allow Administrators group to make remote calls to SAM
# 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\Control\Lsa').GetValueKind('RestrictRemoteSAM').ToString()]) -eq 'reg_sz') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa' -Name 'RestrictRemoteSAM' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'RestrictRemoteSAM') -eq 'O:BAG:BAD:(A;;RC;;;BA)'))
}

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_2016 target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windows:def:1210
$isDomainController = (Get-CimInstance -ClassName Win32_ComputerSystem).DomainRole -eq 5 -or (Get-CimInstance -ClassName Win32_ComputerSystem).DomainRole -eq 4
$samRestricted = (Get-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "RestrictRemoteSAM" -ErrorAction SilentlyContinue).RestrictRemoteSAM -eq "O:BAG:BAD:(A;;RC;;;BA)"
if (($isDomainController -and $samRestricted) -or $samRestricted) { Write-Output "PASS"; Exit 0 } else { Write-Output "FAIL"; Exit 1 }

Remediation

Navigate to the policy Computer Configuration >> Windows Settings >> Security Settings >> Local Policies >> Security Options >> "Network access: Restrict clients allowed to make remote calls to SAM". 

Select "Edit Security" to configure the "Security descriptor:".

Add "Administrators" in "Group or user names:" if it is not already listed (this is the default).

Select "Administrators" in "Group or user names:".

Select "Allow" for "Remote Access" in "Permissions for "Administrators".

Click "OK".

The "Security descriptor:" must be populated with "O:BAG:BAD:(A;;RC;;;BA) for the policy to be enforced.