2FA - do we have to do anything to enable it?

[AstonJ]

Received an email from someone having trouble enabling 2FA - yet I don’t recall ever turning this on or setting up anything for it, do I have to?

Hi,

Sorry for the disturbance.

I’ve created an account today and tried to enable two-factor authentication however the operation constantly fails with the following message “Invalid authentication code. Each code can only be used once.”.

Steps:

1. Go to preferences.
2. Click “Edit” in the 2FA section.
3. Scan a barcode with Google Authenticator app.
4. Enter the code from the GA app.
5. See the error “Invalid authentication code. Each code can only be used once.”.

My main browser is Firefox Dev Edition (62.0b16 (64-bit)) however I’ve tried to perform this action in Safari (Version 11.1.2 (13605.3.8)).

Several attempts have been performed in each browser.

Could you please take a look and assist?

Thanks.

[jomaxro (Joshua Rosenfeld)]

2FA was added back in early March. See Discourse 2.0.0.beta4 Release Notes. You (a Discourse site admin) shouldn’t need to do anything.

@featheredtoast may have some suggestions on what to try (or to ask the user to try) to get this working.

[AstonJ]

Thanks

Is there anyway we can disable it? I haven’t looked into it so not sure how it works, but I don’t like the idea of having to rely on (or send user info to) a third party.

[jomaxro (Joshua Rosenfeld)]

I don’t believe it can be disabled, no. Also, no data is being sent to a third party.

Here’s a quick summary of 2FA: Discourse implemented the TOTP (time-based one time password) algorithm. When a user decides to enable 2FA they are presented with a QR code (or a long string of characters). That string is used by an authentication app (like Google Authenticator, Microsoft Authenticator, Authy, YubiKey, etc.) to generate a new 6-digit password every 30 seconds. Those apps are in no way connected to your Discourse site, nor do they have any user info. They simply generate a code every 30 seconds. Your Discourse site also knows what those codes are, so when a user tries to log in, after entering their username and password they’re asked for a code. They check their app, enter the code, and the server checks if it’s the same code it expected.

Does that make sense?

[featheredtoast (Jeff Wong)]

A good thing to check is whether or not the server time is in sync with the world (generally through ntp).

Having an incorrect time can cause some interesting errors as this protocol is time based.

[AstonJ]

Thanks both

@jomaxro

Your Discourse site also knows what those codes are, so when a user tries to log in, after entering their username and password they’re asked for a code. They check their app, enter the code, and the server checks if it’s the same code it expected.

Does it need to connect to a third party to learn/check what those codes are? Or is it all generated on my server?

@featheredtoast

A good thing to check is whether or not the server time is in sync with the world (generally through ntp).

Having an incorrect time can cause some interesting errors as this protocol is time based.

Just checked the time and it’s fine.. would timezones matter? I’m guessing the person is in a different timezone to that of what is set for the server.

[riking (Kane York)]

Ask the user to use the “Time correction for codes” operation in the app’s settings.

[supermathie (Michael Brown)]

@AstonJ

Does it need to connect to a third party to learn/check what those codes are? Or is it all generated on my server?

Not at all - it is 100% on the server.

@AstonJ

Just checked the time and it’s fine… would timezones matter?

No. It’s based off UTC; not local time.

What may help is if you want to check what the server’s opinion of the current code is you can use e.g. from the rails console:

pry(main)> User.find_by(username: "Supermathie").totp.now
=> "319971"

[sampoullain]

관리자가 특정 사용자의 2단계 인증을 끄는 것이 가능한가요?

그렇게 할 수 있는 옵션이 있는 것 같지 않은데, 우리 커뮤니티의 한 멤버가 2단계 인증이 설정되어 있어 계정에 로그인하지 못하고 있습니다.

[jomaxro (Joshua Rosenfeld)]

사용자 인터페이스에서 2FA를 비활성화할 수 없으며, 이를 수행하려면 rails 콘솔 접근 권한이 필요합니다. How to disable 2FA - #11 by featheredtoast 를 참조하세요.

[JammyDodger]

이 기능에 대한 작은 업데이트가 있습니다 - 이제 관리자는 각 사용자의 /admin/users 페이지에서 다른 사용자의 2FA를 비활성화할 수 있습니다.