[REQ-DC-085] Enable Dynamic Signature Dropped Event Reporting on Domain Controllers

Target Scope

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

Implementation Details

• Priority: Low
• GPO Path / Registry Location:
  • GPO Path: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Reporting
  • Registry Location:
    • HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Reporting
      • EnableDynamicSignatureDroppedEventReporting = 1 (REG_DWORD)

Rationale

Enabling this log report generation triggers explicit events when a dynamic scan ruleset signature is dropped. This ensures SIEM integrations can immediately log changes in the local threat signatures dataset.

Legacy Impact & Compatibility

None.

Implementation Steps

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

1. Navigate to: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Reporting
2. Set 'Configure whether to report Dynamic Signature dropped events' to 'Enabled'

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

Download Script: Configure-DefenderDynamicReporting.ps1

# Configure-DefenderDynamicReporting.ps1
$RepPath = "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Reporting"
if (-not (Test-Path $RepPath)) { New-Item -Path $RepPath -Force | Out-Null }
Set-ItemProperty -Path $RepPath -Name "EnableDynamicSignatureDroppedEventReporting" -Value 1 -Type DWord -Force

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

# Get-DefenderDynamicReportingStatus.ps1
$Reg = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Reporting" -Name "EnableDynamicSignatureDroppedEventReporting" -ErrorAction SilentlyContinue
if ($Reg -and $Reg.EnableDynamicSignatureDroppedEventReporting -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