Microsoft 365 Apps are disabling server sign-in prompts using Basic authentication in Office Apps. We are making this change because basic authentication is a legacy authentication method that sends a username and password with each request. As a result, an attacker can access these credentials and use them to access resources. Continued use of Basic Authentication is a big security concern, so we have decided to deprecate it from all tenants. We will retire this feature in Office Apps version 2...
Applies to: Microsoft 365 apps
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).