Blocking WHfB passkey and using Yubikeys only
by soulfulsysadmin
Hello, I am currently working on transitioning our computers from an on-Prem AD environment into a Intune MDM joined, cloud-only environment, along with moving our users from a password+MFA login, to a completely passwordless login. For this we have decided that we would like to use Yubico security keys for authenticating into users' microsoft accounts, and WhfB for easily logging into their computers. Unfortunately, I have found that the use of WHfB on Intune MDM joined devices automatically adds a login.microsoft.com passkey into windows hello, which is always offered first during passwordless sign-in. I cannot find a way to block this behaviour or modify which passkey storage windows offers first. While WHfB passkeys are still very safe compared to passwords, we are (I think quite rightly) concerned that if the end users are not prompted to use their Yubikeys during perioodic reauthentication, they will forget how to use them, and if they set a unique pin on them that they don't reguarly use, then when the need to use their yubikey does actually arise, for instance when they get their next computer or phone, they won't remember it. This also makes periodic reauthentication feel somewhat pointless as the users will just press on their fingerprint scanner and be done with it. I have found exactly one way to change this behaviour, and that is by defining an Entra Authentication strength containing only yubikey AAGUIDs and forcing my intune testing user to adhere to that authentication strength with a conditional access policy, while this does block the ability to use the WHfB microsoft passkey to sign in, the end user experience is very bad, if a users sees this, they won't think that they can't use windows hello to login, they'll think that windows hello is not working correctly. In the gif below, you can see that windows hello offers itself first but silently fails and prompts the user to enter their pin, without any sort of error message. Processing img cabnfg8pqjgh1... (I realise that I specifically selected a windows hello key in the gif, but the behavious is identical when I initially load the login page or if I select log in methods>passkey, windows hello will always offer itself first, even if it cannot function correctly in this case). For personal use, https://github.com/Aldaviva/AuthenticatorChooser solves this issue, and while i am grateful for the fix, random scripts from github aren't really appropriate when configuring important security settings, Is there anything we can here or do we have to wait for MS? submitted by /u/soulfulsysadmin [link] [comments]