PowerPoint: Default File Block Behavior (Do Not Open)
π 2025-10-30
β’
β±οΈ 2 minuten lezen
β’
π’ Should-Have
πΌ Management Samenvatting
Default file block behavior = what happens when blocked file type opened - aanbeveling: 'Do not open' (strict block, no override).
Aanbeveling
IMPLEMENT
Risico zonder
Low
Risk Score
3/10
Implementatie
2u (tech: 1u)
Van toepassing op:
β Microsoft PowerPoint
File block behavior options: 'Do not open': Blocked files CANNOT open (strict - AANBEVOLEN), 'Open in Protected View': Blocked files open read-only (allows viewing maar no editing - less strict), 'Open in Protected View + allow editing': User can enable editing (WEAK - defeats purpose). Best practice: 'Do not open' = Cannot open legacy/dangerous formats (PowerPoint 97-2003, Word 2.x, etc.) β forces modern formats.
Do not open: Policy: Set default file block behavior: Blocked files are not opened, Effect: User opens blocked file type β error message 'File format blocked', No override: User CANNOT open (forced compliance), Modern formats: .pptx works (not blocked).
Intune Settings Catalog: PowerPoint\Security\Trust Center\File Block Settings β Set default file block behavior: Blocked files are not opened (strict).
Compliance
CIS Office Benchmark, DISA STIG, BIO 12.02.
Monitoring
Gebruik PowerShell-script default-file-block-behavior.ps1 (functie Invoke-Monitoring) β Controleren.
Remediatie
Gebruik PowerShell-script default-file-block-behavior.ps1 (functie Invoke-Remediation) β Herstellen.
Compliance & Frameworks
CIS M365: Control Office - File block behavior (L1) -
BIO: 12.02.01 -
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
Stelt standaard file block gedrag in zodat geblokkeerde bestanden niet worden geopend in PowerPoint
.DESCRIPTION
Dit script implementeert CIS control O365-PT-000004 voor het instellen van het standaard
file block gedrag in Microsoft PowerPoint. Dit zorgt ervoor dat geblokkeerde bestanden niet
worden geopend, wat de beveiliging verbetert tegen potentieel schadelijke bestanden.
.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
.\default-file-block-behavior.ps1 -Monitoring
Controleert of geblokkeerde bestanden niet worden geopend
.EXAMPLE
.\default-file-block-behavior.ps1 -Remediation
Stelt in dat geblokkeerde bestanden niet worden geopend
.NOTES
Registry pad: HKCU:\Software\Policies\Microsoft\Office\16.0\PowerPoint\Security\FileBlock
Waarde: OpenInProtectedView = 0
CIS Control: O365-PT-000004
DISA STIG: Microsoft Office 365 ProPlus v3r3
#>#Requires -Version 5.1param(
[switch]$Monitoring,
[switch]$Remediation,
[switch]$Revert,
[switch]$WhatIf
)
# Globale variabelen$RegistryPath = "HKCU:\Software\Policies\Microsoft\Office\16.0\PowerPoint\Security\FileBlock"
$ValueName = "OpenInProtectedView"
$ExpectedValue = 0$ControlID = "O365-PT-000004"
functionTest-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 ${ControlID}: Standaard file block gedrag instellen" -ForegroundColor Green
try {
if (-not (Test-Path$RegistryPath)) {
Write-Host "β 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 "β Control compliant: ${ValueName} = $ExpectedValue (Geblokkeerde bestanden worden niet geopend)" -ForegroundColor Green
return$true
}
else {
$actualValue = if ($currentValue) { $currentValue.$ValueName } else { "Not Set" }
Write-Host "β Control non-compliant: ${ValueName} = $actualValue (Expected: $ExpectedValue)" -ForegroundColor Red
return$false
}
}
catch {
Write-Host "β Fout bij controleren registry instelling: $($_.Exception.Message)" -ForegroundColor Red
return$false
}
}
function Invoke-Remediation {
Write-Host "Remediating ${ControlID}: Standaard file block gedrag instellen" -ForegroundColor Yellow
try {
if ($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 "β Registry waarde succesvol ingesteld: ${ValueName} = $ExpectedValue" -ForegroundColor Green
Start-Sleep -Seconds 1return Invoke-Monitoring
}
catch {
Write-Host "β Fout bij configureren registry instelling: $($_.Exception.Message)" -ForegroundColor Red
return$false
}
}
function Invoke-Revert {
Write-Host "Reverting ${ControlID}: Standaard file block gedrag herstellen" -ForegroundColor Yellow
try {
if ($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 "β Registry waarde verwijderd: ${ValueName}" -ForegroundColor Green
}
return$true
}
catch {
Write-Host "β Fout bij herstellen registry instelling: $($_.Exception.Message)" -ForegroundColor Red
return$false
}
}
# Hoofd uitvoeringtry {
if ($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: .\default-file-block-behavior.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
Write-Host ""
Write-Host "Handmatige configuratie:" -ForegroundColor Cyan
Write-Host "Group Policy: User Configuration > Administrative Templates > Microsoft PowerPoint 2016" -ForegroundColor White
Write-Host "> PowerPoint Options > Security > Trust Center > File Block Settings" -ForegroundColor White
Write-Host "> Set default file block behavior: Enabled: Blocked files are not opened" -ForegroundColor White
}
}
catch {
Write-Host "β Onverwachte fout: $($_.Exception.Message)" -ForegroundColor Red
exit 1
}
Risico zonder implementatie
Risico zonder implementatie
Low: Low: 'Open in Protected View' = user can enable editing (bypasses block).
Management Samenvatting
PowerPoint file block behavior: 'Do not open' (strict). No override. Forces modern formats. Implementatie: 1-2 uur.