Transcript
A wafrn woot (post) by @tinker@infosec.exchange saying "Microsoft Authenticator needs me to validate with Authenticator in order to log in with Authenticator to use it to authenticate another app with Authenticator. Here is the app telling me to open itself to validate itself with itself. #infosec #iHateComputers" It has a screenshot showing the microsoft authenticator app.
This isn't a Microsoft issue. This is a stupidity issue. Any authenticator you add 2 factor to, and then put the 2 factor in that same app will do this.
Even better/worse, Microsoft will never send 2FA requests to the app that is requesting them. This user has a second copy of Authenticator installed somewhere else which they forgot about.
in a sandbox or VM? or perhaps a rooted phone which does all that and more.