[REQ-DC-079] Prevent MAPS Local Setting Override on Domain Controllers

Target Scope

• Applicable Systems: Domain Controllers.
• Operating Systems: Windows Server 2016 (and above).

Implementation Details

• Priority: Medium
• GPO Path / Registry Location:
  • GPO Path: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\MAPS
  • Registry Location:
    • HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Spynet
      • SpynetReporting = 0 (REG_DWORD)

Rationale

Preventing local overrides of Microsoft Active Protection Service (MAPS) reporting ensures that Domain Controllers consistently report telemetry and signature feedback to cloud resources, preserving centralized protective visibility.

Legacy Impact & Compatibility

Local system administrators cannot opt-out of telemetry reporting.

Implementation Steps

Option A: Group Policy Object (GPO) Configuration (Preferred)

1. Navigate to: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\MAPS
2. Set 'Join Microsoft MAPS' to 'Disabled' (or prevent override to SpynetReporting = 0)

Option B: PowerShell & Registry Configuration (Remediation / Non-GPO)

Download Script: Configure-DefenderSpynetDC.ps1

# Configure-DefenderSpynetDC.ps1
$SpynetPath = "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Spynet"
if (-not (Test-Path $SpynetPath)) { New-Item -Path $SpynetPath -Force | Out-Null }
Set-ItemProperty -Path $SpynetPath -Name "SpynetReporting" -Value 0 -Type DWord -Force

To audit the hardening status: Download Script: Get-DefenderSpynetDCStatus.ps1

# Get-DefenderSpynetDCStatus.ps1
$Reg = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Spynet" -Name "SpynetReporting" -ErrorAction SilentlyContinue
if ($Reg -and $Reg.SpynetReporting -eq 0) {
    Write-Output "Compliant"
    exit 0
} else {
    Write-Output "Non-Compliant"
    exit 1
}

Sources & Compliance References

• CIS Microsoft Windows Server Benchmark: Section 18.9 (Windows Defender Antivirus configuration parameters)
• ANSSI Active Directory Hardening Guide: Protective controls baselines on Domain Controllers