Office 365 to let admins block Active Content on Trusted Docs | Bleeping Computer

End-users will be unable to disregard institution-wide policies set up to block active content on Trusted Documents, according to Microsoft. Trusted docs, according to Redmond, are files that open without warnings when active content has been enabled (e.g., ActiveX controls, macros, and Dynamic Data Exchange (DDE) routines that don’t require user intervention). Trusted documents will open without prompting even if new (potentially malicious) active content is added, bypassing Office’s Protected View, which opens documents from possibly dangerous areas as read-only. 

Source: https://www.bleepingcomputer.com/news/security/office-365-to-let-admins-block-active-content-on-trusted-docs/