But I'm not saying you should care about this. Everyone can make their own risk assessment, especially if you know about common attacks like the data breaches that you mention
This is a category error. The 2FA seed token may be a string of bytes just like the password, but the seed is never communicated outside your device. That makes them different types of secrets: a capture of the transmitted login codes will not compromise the 2FA seed. Even if you auto-generate the password in the same way, it's the actual valuable secret that needs to leave your device -- by design.
I don't know if a website database breach compromises both keys. Is the 2FA seed a pre-shared key, or is the algorithm asymmetric? I seriously hope it's the latter, but I don't know for sure.
I'll be interested in a asymmetric variant although I'll probably use a popular library and call it a day if I have to get involved in 2FA.
[1]: https://auth0.com/blog/the-working-principles-of-2fa-2-facto...
It’s been a while since I did any crypto. But it feels like the shortness of the one-time-code probably makes it impossible to do asymmetrically. If this is indeed the case there is probably an elegant proof or some better way of thinking about why it’s impossible. I would be interested in reading that.
1. The attacker either captures the OTPs on the real website, or on a phishing page. They do not have access to either the website's store of 2FA tokens, nor your password vault.
and
2a. Having you enter one or two OTPs on the login page is not enough. The phishing page can claim "wrong OTP, you can try again in 30 seconds" to get at least two codes. The attacker can open a login session and go to down immediately when you enter it, but if there is a protocol where there's a delay of e.g. 24 hours, they would need to phish you again after 24 hours and that's unusual for them to bother with (beyond opportunistically) as far as I know
or
2b. The attack isn't automated and the attacker is also not laying in wait for someone to fall for the phishing (like when having sent 10 phishing emails and waiting for one employee to bite such that they can get into an organisation). In that case, the OTP almost certainly has expired and can't be used anymore
While #1 is common, #2 is rare as far as I'm aware. Once you're into an account, you usually can navigate to e.g. a transaction page within a few seconds and then enter the same OTP¹ again (because the time window hasn't expired yet) or ask the user for a new one a few seconds later as described
A great protection against this would be a device that displays what it is that you're authorising, such as these old bank card readers that show on a little screen like "login" or "transaction of 1337€ to NL00RABO0123456789", but these go well beyond the standard 2FA seeds that you can store in a vault
Either way, you're right, there is this benefit of having 2FA even if you store them together. If this is within one's threat model, but theft of your vault is not as big a concern, it's a valid solution
¹Yes, OTP can never be the "same" by definition. But this works in 9 out of 10 customer sites that we see (security consultancy firm; thoughts are my own yada yada)
Most sites require 2FA for changing the password, but do not require the password for changing itself.
If the threat model does not include info-stealers (and instead includes only phishing and in general getting passwords/codes intercepted, getting a website with bad security compromised etc) then having the TOTPs in the same device does not really increase risk.
Imo in the first case, one should probably not have the passwords on the phone either. Use a phone for the OTPs and computer for the passwords for example. But that is very impractical and carries increased risk of (temporarily) not being able to access stuff in certain situations. It could be a good thing depending on what one wants to guard themselves against. If your goal is to have better security than most people, using a good password manager that is not a browser and 2FAs is as many services as possible already carries you very far. If you due to work etc you have increased risk of being targeted, prob more is needed.
... and having TOTPs at all does not decrease any risk, either. There's no benefit to the situation where you store 2 good secrets in 1 place as compared to storing 1 good secret in 1 place.
Over this entire thread you keep repeating this, and you're so confidently wrong.
If a hacker (or shoulder peeper) gets my password to a site without a TOTP, they can login. 1FA. If I also use a TOTP adjacently, the hacker can't login and the shoulder peeper has a window of 30 seconds.
Its 2FA. Storing critical TOTPs in your password manager is bad practice and thus bad 2FA, but its still 2FA.
