Users customizing attachment security settings must be prevented.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-228438	DTOO238	SV-228438r508021_rule		Medium

Description

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.

STIG	Date
Microsoft Outlook 2016 Security Technical Implementation Guide	2022-03-11

Details

Check Text (C-30671r497636_chk)

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 (F-30656r497637_fix)

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