Visio must automatically disable unsigned add-ins without informing users.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-223395 | O365-VI-000003 | SV-223395r1016173_rule | CCI-003992 | medium |
| Description | ||||
| This policy setting controls whether the specified Office application notifies users when unsigned application add-ins are loaded or silently disable such add-ins without notification. This policy setting only applies if the "Require that application add-ins are signed by Trusted Publisher" policy setting is enabled, which prevents users from changing this policy setting. If this policy setting is enabled, applications automatically disable unsigned add-ins without informing users. If this policy setting is disabled, if this application is configured to require that all add-ins be signed by a trusted publisher, any unsigned add-ins the application loads will be disabled and the application will display the Trust Bar at the top of the active window. The Trust Bar contains a message that informs users about the unsigned add-in. If this policy setting is not configured, the disable behavior applies, and in addition, users can configure this requirement themselves in the "Add-ins" category of the Trust Center for the application. | ||||
| STIG | Date | |||
| Microsoft Office 365 ProPlus Security Technical Implementation Guide | 2025-03-05 | |||
Details
Check Text (C-223395r1016173_chk)
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Visio 2016 >> Visio Options >> Security >> Trust Center >> Disable Trust Bar Notification for unsigned application add-ins and block them is set to Enabled.
Use the Windows Registry Editor to navigate to the following key:
HKCU\software\policies\microsoft\office\16.0\visio\security
If the value notbpromptunsignedaddin is REG_DWORD = 1, this is not a finding.
Fix Text (F-25056r442405_fix)
Set the policy value for User Configuration >> Administrative Templates >> Microsoft Visio 2016 >> Visio Options >> Security >> Trust Center >> Disable Trust Bar Notification for unsigned application add-ins and block them to Enabled.