So my company decided to migrate office suite and email etc to Microsoft365. Whatever. But for 2FA login they decided to disable the option to choose “any authenticator” and force Microsoft Authenticator on the (private) phones of both employees and volunteers. Is there any valid reason why they would do this, like it’s demonstrably safer? Or is this a battle I can pick to shield myself a little from MS?
Ms auth is a mobile only application. Not even available on windows or macOS. The point of it is to provide a second factor of authentication in the for of “something you have”. There are a few factors that can be used for authentication. Something you know (password), something you have (hardware like a key or a phone), and something you are (iris scan, DNA, fingerprint, other biometric). Ms auth uses something you have and something you are to authenticate most users. You provide a password and then you prove you have your cellphone and your cellphone checks your biometrics to see if you are you. In that way, it is effectively checking all 3 factors.
Why couldn’t “laptop” be a second factor?
It is using windows hello on compatible machines and through persistent tokens on Mac and Windows machines not compatible with hello. You have to create that token with a known factor such as a mobile device but outside of that, users almost never have to sign in with persistent tokens.