PowerPoint: Disable Automatic Download Of Linked Images

πŸ’Ό Management Samenvatting

Disable automatic download of linked images - prevents tracking pixels + malicious external content (privacy + security).

Aanbeveling
IMPLEMENT
Risico zonder
Low
Risk Score
4/10
Implementatie
3u (tech: 1u)
Van toepassing op:
βœ“ Microsoft PowerPoint

Linked images = tracking + malware: Linked images: PowerPoint slide contains URL to external image (http://attacker.com/image.png), Auto-download: PowerPoint fetches image when presentation opened, Tracking pixel: 1x1 transparent image β†’ attacker logs: IP address, timestamp, user agent (presentation opened by whom, when, where), Malicious content: Image URL β†’ malware download, exploit kit. Defense: Block auto-download β†’ images NOT fetched β†’ tracking fails.

PowerShell Modules Vereist
Primary API: Intune / GPO
Connection: Registry-based
Required Modules:

Implementatie

Disable image auto-download: Policy: Disable automatic download of linked images: Enabled, Effect: Linked images NOT automatically fetched from external URLs, User: Sees placeholder (can manually download if trusted), Embedded images: Unaffected (images IN file, not external URLs).

Vereisten

  1. PowerPoint 2016+
  2. Intune of GPO

Implementatie

Intune Settings Catalog: PowerPoint\Security β†’ Disable automatic download of linked images: Enabled. User training: Embed images (not link) for better performance + security.

Compliance

AVG Art. 32 (Privacy - tracking prevention), BIO 08.01.

Monitoring

Gebruik PowerShell-script unblock-automatic-download-linked-images-disabled.ps1 (functie Invoke-Monitoring) – Controleren.

Remediatie

Gebruik PowerShell-script unblock-automatic-download-linked-images-disabled.ps1 (functie Invoke-Remediation) – Herstellen.

Compliance & Frameworks

Automation

Gebruik het onderstaande PowerShell script om deze security control te monitoren en te implementeren. Het script bevat functies voor zowel monitoring (-Monitoring) als remediation (-Remediation).

PowerShell
<# .SYNOPSIS Behoudt blokkering van automatische download van gelinkte afbeeldingen in PowerPoint .DESCRIPTION Dit script implementeert CIS control O365-PT-000007 voor het uitschakelen van de mogelijkheid om automatische downloads van gelinkte afbeeldingen te deblokkeren in Microsoft PowerPoint. Dit voorkomt dat externe content automatisch wordt gedownload, wat privacy en beveiligingsrisico's vormt. .REQUIREMENTS - PowerShell 5.1 of hoger - Lokale administrator rechten voor registry wijzigingen - Microsoft PowerPoint geΓ―nstalleerd .PARAMETER Monitoring Controleert de huidige compliance status .PARAMETER Remediation Past de aanbevolen configuratie toe .PARAMETER Revert Herstelt de originele configuratie .PARAMETER WhatIf Toont wat er zou gebeuren zonder wijzigingen door te voeren .EXAMPLE .\unblock-automatic-download-linked-images-disabled.ps1 -Monitoring Controleert of automatische download deblokkering is uitgeschakeld .EXAMPLE .\unblock-automatic-download-linked-images-disabled.ps1 -Remediation Schakelt automatische download deblokkering uit .NOTES Registry pad: HKCU:\Software\Policies\Microsoft\Office\16.0\POWERPOINT\Security Waarde: unblockautomaticdownloadlinkedimagesdisabled = 1 CIS Control: O365-PT-000007 DISA STIG: Microsoft Office 365 ProPlus v3r3 #> #Requires -Version 5.1 param( [switch]$Monitoring, [switch]$Remediation, [switch]$Revert, [switch]$WhatIf ) # Globale variabelen $RegistryPath = "HKCU:\Software\Policies\Microsoft\Office\16.0\POWERPOINT\Security" $ValueName = "unblockautomaticdownloadlinkedimagesdisabled" $ExpectedValue = 1 $ControlID = "O365-PT-000007" function Test-Compliance { try { if (-not (Test-Path $RegistryPath)) { return $false } $currentValue = Get-ItemProperty -Path $RegistryPath -Name $ValueName -ErrorAction SilentlyContinue return ($currentValue -and $currentValue.$ValueName -eq $ExpectedValue) } catch { return $false } } function Invoke-Monitoring { Write-Host "Monitoring ${ControlID}: Automatische download deblokkering uitschakelen" -ForegroundColor Green try { if (-not (Test-Path $RegistryPath)) { Write-Host "βœ— Registry pad bestaat niet: $RegistryPath" -ForegroundColor Red return $false } $currentValue = Get-ItemProperty -Path $RegistryPath -Name $ValueName -ErrorAction SilentlyContinue if ($currentValue -and $currentValue.$ValueName -eq $ExpectedValue) { Write-Host "βœ“ Control compliant: ${ValueName} = $ExpectedValue" -ForegroundColor Green return $true } else { $actualValue = if ($currentValue) { $currentValue.$ValueName } else { "Not Set" } Write-Host "βœ— Control non-compliant: ${ValueName} = $actualValue (Expected: $ExpectedValue)" -ForegroundColor Red return $false } } catch { Write-Host "βœ— Fout bij controleren registry instelling: $($_.Exception.Message)" -ForegroundColor Red return $false } } function Invoke-Remediation { Write-Host "Remediating ${ControlID}: Automatische download deblokkering uitschakelen" -ForegroundColor Yellow try { if ($WhatIf) { Write-Host "WhatIf: Zou registry waarde instellen: ${ValueName} = $ExpectedValue" -ForegroundColor Cyan return $true } if (-not (Test-Path $RegistryPath)) { Write-Host "Registry pad aanmaken: $RegistryPath" -ForegroundColor Yellow New-Item -Path $RegistryPath -Force | Out-Null } Set-ItemProperty -Path $RegistryPath -Name $ValueName -Value $ExpectedValue -Type DWord -Force Write-Host "βœ“ Registry waarde succesvol ingesteld: ${ValueName} = $ExpectedValue" -ForegroundColor Green Start-Sleep -Seconds 1 return Invoke-Monitoring } catch { Write-Host "βœ— Fout bij configureren registry instelling: $($_.Exception.Message)" -ForegroundColor Red return $false } } function Invoke-Revert { Write-Host "Reverting ${ControlID}: Automatische download deblokkering herstellen" -ForegroundColor Yellow try { if ($WhatIf) { Write-Host "WhatIf: Zou registry waarde verwijderen: ${ValueName}" -ForegroundColor Cyan return $true } if (Test-Path $RegistryPath) { Remove-ItemProperty -Path $RegistryPath -Name $ValueName -ErrorAction SilentlyContinue Write-Host "βœ“ Registry waarde verwijderd: ${ValueName}" -ForegroundColor Green } return $true } catch { Write-Host "βœ— Fout bij herstellen registry instelling: $($_.Exception.Message)" -ForegroundColor Red return $false } } # Hoofd uitvoering try { if ($Monitoring) { $result = Invoke-Monitoring exit $(if ($result) { 0 } else { 1 }) } elseif ($Remediation) { $result = Invoke-Remediation exit $(if ($result) { 0 } else { 1 }) } elseif ($Revert) { $result = Invoke-Revert exit $(if ($result) { 0 } else { 1 }) } else { Write-Host "Gebruik: .\unsafe-locations-protected-view-enabled.ps1 [-Monitoring] [-Remediation] [-Revert] [-WhatIf]" -ForegroundColor Yellow Write-Host " -Monitoring: Controleer huidige compliance status" -ForegroundColor White Write-Host " -Remediation: Pas aanbevolen configuratie toe" -ForegroundColor White Write-Host " -Revert: Herstel originele configuratie" -ForegroundColor White Write-Host " -WhatIf: Toon wat er zou gebeuren" -ForegroundColor White } } catch { Write-Host "βœ— Onverwachte fout: $($_.Exception.Message)" -ForegroundColor Red exit 1 }

Risico zonder implementatie

Risico zonder implementatie
Low: Low: Linked images = tracking pixels (privacy invasion) + malware vector.

Management Samenvatting

Disable PowerPoint linked image auto-download. Privacy + security. Embed images instead. Implementatie: 1-3 uur.