Users customizing attachment security settings must be prevented.

From Microsoft Outlook 2016 Security Technical Implementation Guide

Associated with: CCI-001170

SV-85779r1_rule Users customizing attachment security settings must be prevented.

Vulnerability discussion

This policy setting prevents users from overriding the set of attachments blocked by Outlook. If you enable this policy setting users will be prevented from overriding the set of attachments blocked by Outlook. Outlook also checks the "Level1Remove" registry key when this setting is specified. If you disable or do not configure this policy setting, users will be allowed to override the set of attachments blocked by Outlook.

Check content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security "Prevent users from customizing attachment security settings" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\16.0\outlook Criteria: If the value DisallowAttachmentCustomization is REG_DWORD = 1, this is not a finding.

Fix text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Security "Prevent users from customizing attachment security settings" to "Enabled".

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