PowerPoint: Make Hidden Markup Visible

πŸ’Ό Management Samenvatting

Make hidden markup visible in PowerPoint - prevents accidental information disclosure via hidden comments/annotations.

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

Hidden markup = data leakage: PowerPoint markup: Comments, reviewer annotations, tracked changes, hidden slides, speaker notes, Hidden content: Visible to author (during editing) BUT hidden in presentation mode, Data leakage scenario: Confidential comment 'DO NOT share pricing with customer' β†’ hidden during presentation BUT visible if recipient opens file in edit mode. Attack: External recipient opens .pptx β†’ sees hidden comments β†’ sensitive info leaked. Make visible: Forces authors to SEE hidden markup (awareness) β†’ remove before sharing.

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

Implementatie

Make markup visible: Policy: 'Make hidden markup visible': Enabled, Effect: PowerPoint shows hidden comments/annotations in presentation mode (author awareness), Workflow: Author creates presentation β†’ sees hidden markup during review β†’ removes confidential comments β†’ shares clean file. Alternative: Document Inspector (manual cleanup).

Vereisten

  1. PowerPoint 2016+
  2. Intune of GPO
  3. User training: Remove hidden markup before sharing

Implementatie

Intune Settings Catalog: PowerPoint\Security β†’ Make hidden markup visible: Enabled. Training: Users run Document Inspector (File β†’ Info β†’ Check for Issues β†’ Inspect Document) before external sharing.

Compliance

BIO 08.02 (Information classification), ISO 27001 A.8.2.3 (Information labeling).

Monitoring

Gebruik PowerShell-script make-hidden-markup-visible.ps1 (functie Invoke-Monitoring) – Controleren.

Remediatie

Gebruik PowerShell-script make-hidden-markup-visible.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 Maakt verborgen markup zichtbaar in PowerPoint .DESCRIPTION Dit script implementeert CIS control O365-PT-000001 voor het zichtbaar maken van verborgen markup in Microsoft PowerPoint. Dit voorkomt dat gevoelige informatie verborgen blijft in presentaties die worden gedeeld. .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 .\make-hidden-markup-visible.ps1 -Monitoring Controleert of verborgen markup zichtbaar wordt gemaakt .EXAMPLE .\make-hidden-markup-visible.ps1 -Remediation Maakt verborgen markup zichtbaar .NOTES Registry pad: HKCU:\Software\Policies\Microsoft\Office\16.0\POWERPOINT\Security Waarde: makehiddenmarkupvisible = 1 CIS Control: O365-PT-000001 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 = "makehiddenmarkupvisible" $ExpectedValue = 1 $ControlID = "O365-PT-000001" 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}: Verborgen markup zichtbaar maken" -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 ${ControlID}: Verborgen markup zichtbaar maken" -ForegroundColor Yellow try { if ($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 ${ControlID}: Verborgen markup instelling herstellen" -ForegroundColor Yellow try { if ($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: .\network-trusted-locations-disabled.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: Hidden markup = accidental confidential info disclosure.

Management Samenvatting

Make PowerPoint hidden markup visible. Prevent data leakage via comments. Train users: Document Inspector. Implementatie: 1-4 uur.