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?
Yeah but you install that stuff on your work computer. If my job requires me to use an authenticator on a non-work phone, then at least let me use the one I'm already using.
I'm not concerned per se and I definitely applaud the MFA requirement. I mean I hate MS and don't like apps I don't need, and I don't trust them, but as others pointed out this would mostly just be whiny. That's why I asked for reasons why restricting users to MS Authenticator would be preferable. If it's more secure or technically way easier and thus cheaper to maintain then fine, I'll find an acceptable way to comply. If not, then it's them who are whiny and I'd rather make the case to let us use whatever authenticator we already have installed.
But MS Authenticator isn’t a normal 6-digit Authenticator; it scans your Face ID (or finger print) and in many cases (like my work) it can be support password less accounts (relying only on something you have and something you are).
And in regard to your point that you don’t want to install apps you don’t need, it sounds like you do in fact need this app.
reasons why restricting users to MS Authenticator would be preferable
As a security professional:
Under most situations, it is equally as good as any other 2FA app.
Within the Microsoft ecosystem, it provides additional security features above and beyond simple 2FA.
If your workplace is leaning heavily on the Microsoft ecosystem, especially their cloud offerings like Azure, then restricting employees to the Microsoft app is a no-brainer, and actually quite reasonable.
For example, if they happen to have a hybrid domain with an on-prem domain controller syncing with Azure (forgive me for using obsolete terms, I’m a greybeard), then they can control all access to all company assets, including 2FA. If an employee leaves the company, they can also disable the Microsoft app at a moment’s notice by disabling the employee’s Microsoft account. Because everything is hooked into Azure, it sends push notifications down to all company assets - like the Microsoft 2FA app - to unhook all of the company’s credentials and prevent employee access after the fact.
This is disingenuous though... You can simply reset the TOTP seed on any account to achieve the same operation. We use AuthLite on a local domain... I can disable an account domain-wide by simply resetting the TOTP seed or disabling the account. Using an Azure domain and MS app doesn't add any value in that regards. All of the online office stuff can be linked onto a local domain as well and would also be disabled.
I don't care whether it stores the location. The problem is that it sends it to your employer. And so do all Microsoft apps. Teams for example makes full reports for managers to peruse about all kinds of information taken from each employee's device, including location and whether they were using the device and when.
AFAIK on Android it has a hard dependency on Google services. I don't mind installing proprietary stuff to my work profile for the express purposes of work but that requires modifying my system to accommodate this specific app and that's a step too far for my personal device. So I use a free software option (Aegis) instead.
edit: if for some reason I really did need MS Authenticator and not any old TOTP app, I would procure a googled device specifically for work rather than install google or microG into my personal device.