Just got a 2FA prompt on my phone, asking me to select one of three numbers to log in.

Seeing how every other 2FA thing like this doesn’t send those prompts unless you have entered the correct password I got quite concerned.

However, it seems that is the first thing you get after correctly entering your email address, tried on a separate computer that I have never used my email on with a VPN to another country, and I instantly got the 2FA prompt without entering my password.

Imo it’s a very shit way to do it. I can see some pensioner or similar accidentally just clicking a number and then it’s 1 in 3 they get in (assuming they have 2FA to begin with, but still.).

Anyway, figured I’d post it just in case someone else got spooked the same way. I’d also like to know if someone thinks it is a good idea having it work this way and why?

  • kjake@infosec.pub
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    1 year ago

    Microsoft and Okta (that I know of) have implemented this number matching to deal with Push MFA fatigue, but also when certain risk factors make your login look riskier (i.e. impossible travel from an IP located so far away from your last login IP, you couldn’t have physically travelled to the new location in the time since the last login).

    More info: https://techcommunity.microsoft.com/t5/microsoft-entra-azure-ad-blog/advanced-microsoft-authenticator-security-features-are-now/ba-p/2365673

    edited to share a better link

  • Yeah2206@infosec.pub
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    1 year ago

    I believe this is how Microsoft implements verification so that users do not have to remember their passwords. You can probably disable it in Security > Advanced security options > Send sign-in notifications.

    Personally, I find this very convenient, especially when logging into a new device/app/service for the first time. However, I imagine that if someone else is trying to get into my account online, it would be the first thing I disable, switching back to entering my password by default.