[REQ-END-070] Configure Security Intelligence Update Schedule

Target Scope

Applicable Systems: Tier 2 client workstations and member servers.
Operating Systems: Windows 10 (and above) Enterprise/Professional, Windows Server 2016 (and above).

Implementation Details

Priority: Medium
GPO Path / Registry Location:
- GPO Path: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Security Intelligence Updates
- Registry Location:
  - HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates
    - ASSignatureDue = 7 (REG_DWORD)
  - HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates
    - AVSignatureDue = 7 (REG_DWORD)
  - HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates
    - ScheduleDay = 0 (REG_DWORD)

Rationale

Antivirus signatures must remain fresh to block the latest published threats. Mandating daily checks for updates and marking signatures older than 7 days as out-of-date ensures continuous defense parity.

Legacy Impact & Compatibility

Requires continuous outbound connectivity to WSUS or Microsoft Update endpoints.

Implementation Steps

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

Navigate to: Computer Configuration\Administrative Templates\Windows Components\Windows Defender Antivirus\Security Intelligence Updates
Set 'Define the number of days before spyware security intelligence is considered out of date' to 'Enabled' (7 days)
Set 'Define the number of days before virus security intelligence is considered out of date' to 'Enabled' (7 days)
Set 'Specify the day of the week to check for security intelligence updates' to 'Enabled' (Every day or 0)

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

Download Script: Configure-DefenderUpdateSchedule.ps1

# Configure-DefenderUpdateSchedule.ps1
$SigPath = "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates"
if (-not (Test-Path $SigPath)) { New-Item -Path $SigPath -Force | Out-Null }
Set-ItemProperty -Path $SigPath -Name "ASSignatureDue" -Value 7 -Type DWord -Force
Set-ItemProperty -Path $SigPath -Name "AVSignatureDue" -Value 7 -Type DWord -Force
Set-ItemProperty -Path $SigPath -Name "ScheduleDay" -Value 0 -Type DWord -Force

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

# Get-DefenderUpdateScheduleStatus.ps1
$Reg = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates" -Name "ASSignatureDue" -ErrorAction SilentlyContinue
$RegAV = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates" -Name "AVSignatureDue" -ErrorAction SilentlyContinue
$RegDay = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates" -Name "ScheduleDay" -ErrorAction SilentlyContinue
if (($Reg -and $Reg.ASSignatureDue -eq 7) -and ($RegAV -and $RegAV.AVSignatureDue -eq 7) -and ($RegDay -and $RegDay.ScheduleDay -eq 0)) {
    Write-Output "Compliant"
    exit 0
} else {
    Write-Output "Non-Compliant"
    exit 1
}

Sources & Compliance References

CIS Microsoft Windows 10 Benchmark: Section 18.9 (Windows Defender Antivirus configuration parameters)
ANSSI Active Directory Hardening Guide: Protective controls baselines on client workstations

REQ-END-070 - Configure Security Intelligence Update Schedule