When a user designs a custom form in Outlook and attempts to bind an Address Information field to a combination or formula custom field, Outlook must automatically deny it.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-223367	O365-OU-000022	SV-223367r961779_rule		Medium

Description

This policy setting controls what happens when a user designs a custom form in Outlook and attempts to bind an Address Information field to a combination or formula custom field. If you enable this policy setting, you can choose from four different options when an untrusted program attempts to access address information using the UserProperties. Find method of the Outlook object model: - Prompt user. The user will be prompted to approve every access attempt. - Automatically approve. Outlook will automatically grant programmatic access requests from any program. This option can create a significant vulnerability, and is not recommended. - Automatically deny. Outlook will automatically deny programmatic access requests from any program. - Prompt user based on computer security. Outlook will only prompt users when antivirus software is out of date or not running. If you disable or do not configure this policy setting, when a user tries to bind an address information field to a combination or formula custom field in a custom form, Outlook relies on the setting configured in the "Programmatic Access" section of the Trust Center.

STIG	Date
Microsoft Office 365 ProPlus Security Technical Implementation Guide	2025-03-05

Details

Check Text (C-25040r442320_chk)

Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Outlook 2016 >> Security >> Security Form Settings >> Programmatic Security >> Configure Outlook object model prompt when accessing the Formula property of a UserProperty object is set to "Enabled (Automatically Deny)".

Use the Windows Registry to navigate to the following key:

HKCU\Software\Policies\Microsoft\Office\16.0\outlook\security

If the value PromptOOMFormulaAccess is REG_DWORD = 0, this is not a finding.

Fix Text (F-25028r863214_fix)

Set the policy value for User Configuration >> Administrative Templates >> Microsoft Outlook 2016 >> Security >> Security Form Settings >> Programmatic Security >> Configure Outlook object model prompt When accessing the Formula property of a UserProperty object to "Enabled (Automatically Deny)".