Ensure 'Turn off Protected View for attachments opened from Outlook' is set to 'Disabled'

HighLevel 1Automatedoffice

Description

This policy setting determines if Excel files in Outlook attachments open in Protected View. The recommended state for this setting is: Disabled. Rationale: Email is a common vector for spreading files containing malicious code. Disabling Protected View changes this default behavior and could allow malicious code to execute on a user's computer or across the network. User setting: the audit checks HKEY_USERS\<SID>\SOFTWARE\Policies\Microsoft\office\16.0\excel\security\protectedview:disableattachmentsinpv (REG_DWORD) in every loaded user hive (S-1-5-21-*) and is compliant when each holds 0. It prints 'no-user-hive-loaded' (FAIL) when no user profile is loaded, so scan while users are logged on.

How it is checked

Audit method: Windows registry

registry

$sids = @(Get-ChildItem -Path 'Registry::HKEY_USERS' -ErrorAction SilentlyContinue | Where-Object { $_.PSChildName -match '^S-1-5-21-\d+-\d+-\d+-\d+$' } | ForEach-Object { $_.PSChildName }); if ($sids.Count -eq 0) { 'no-user-hive-loaded' } else { $bad = @(); foreach ($s in $sids) { $v = (Get-ItemProperty -Path ('Registry::HKEY_USERS\' + $s + '\SOFTWARE\Policies\Microsoft\office\16.0\excel\security\protectedview') -Name 'disableattachmentsinpv' -ErrorAction SilentlyContinue).'disableattachmentsinpv'; if (-not ($null -ne $v -and @(0) -contains [int64]$v)) { $bad += $s + ':disableattachmentsinpv=' + $v } }; if ($bad.Count -eq 0) { 'compliant' } else { 'non-compliant: ' + ($bad -join ', ') } }

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Configure through Group Policy (User Configuration): User Configuration\Administrative Templates\Microsoft Excel 2016\Excel Options\Security\Trust Center\Protected View\Turn off Protected View for attachments opened from Outlook = Disabled

Properties

Operating systems: Any
Tags: officeproductivitycis-l1
Reference: CIS Microsoft Office Enterprise Benchmark v2.0.0 - 2.2.4.7.2.3.6 Ensure 'Turn off Protected View for attachments opened from Outlook' is set to 'Disabled'

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target office