[REQ-DC-097] Configure Behavioral Network Remote Encryption Protection Aggressiveness on Domain Controllers

Target Scope

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

Implementation Details

• Priority: High
• GPO Path / Registry Location:
  • GPO Path: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Remediation\Behavioral Network Blocks
  • Registry Location:
    • HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Remediation\Behavioral Network Blocks\Remote Encryption Protection
      • RemoteEncryptionProtectionAggressiveness = 1 (REG_DWORD)

Rationale

Ransomware groups target SYSVOL and SYSVOL shares on Domain Controllers to deploy encrypted templates or payloads. Enabling remote encryption protection aggressiveness blocks remote network-driven encryption attempts immediately.

Legacy Impact & Compatibility

None. Blocks behavioral patterns matching ransomware network encryption engines.

Implementation Steps

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

1. Navigate to: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Remediation\Behavioral Network Blocks
2. Set 'Configure behavioral network remote encryption protection aggressiveness' to 'Enabled' (Select '1')

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

Download Script: Configure-DefenderRemoteEncryptionProtection.ps1

# Configure-DefenderRemoteEncryptionProtection.ps1
$Path = "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Remediation\Behavioral Network Blocks\Remote Encryption Protection"
if (-not (Test-Path $Path)) { New-Item -Path $Path -Force | Out-Null }
Set-ItemProperty -Path $Path -Name "RemoteEncryptionProtectionAggressiveness" -Value 1 -Type DWord -Force

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

# Get-DefenderRemoteEncryptionProtectionStatus.ps1
$Path = "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Remediation\Behavioral Network Blocks\Remote Encryption Protection"
$Reg = Get-ItemProperty -Path $Path -Name "RemoteEncryptionProtectionAggressiveness" -ErrorAction SilentlyContinue
if ($Reg -and $Reg.RemoteEncryptionProtectionAggressiveness -eq 1) {
    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