Ask HN: How does Quora auto login work?

https://news.ycombinator.com/item?id=12970964

by starbucksswa • 10 years ago

16 9 10 years ago

news.ycombinator.com

The website automatically logins to my account without entering mail address and password. How does this work even though after restarting router, clearing cache & cookies of browser?

dingdongding• 10 years ago

May be you are using Gmail/Facebook login which is already signed in ?

RickS• 10 years ago

Nope - I get auto logged in via their links as well, but don't use any 3rd party auth.

tchadwick• 10 years ago

Are the links from the emails they send out? Might be a token in those links. I don't have any quora emails right now to check.

Terribledactyl• 10 years ago

Does it work when you switch between browsers and do you happen to be on OS X? Something might live on in keychain/cloud whatever.

They could potentially be using something based on this, https://panopticlick.eff.org

vmorgulis• 10 years ago

May be with an ETag:

https://en.wikipedia.org/wiki/HTTP_ETag

bbcbasic• 10 years ago

ETag is for notifying that content has been updated, so how would you use the mechanism to log someone in?

niftich• 10 years ago

You can exploit the fact that HTTP caching sends the ETag back and forth. A server can set a crafted ETag and basically use it as a session ID. See [1][2]

[1] http://security.stackexchange.com/questions/12679/how-can-i-... [2] https://github.com/lucb1e/cookielesscookies/blob/master/inde...

mickronome• 10 years ago

Don't know, I do however have a problem with Quora that is probably related to whatever way they achieve their auto login. I have an Quora account, but at some point in time I accidentally clicked register instead of login, and now I'm permanently stuck in the registration process. Can't login, and the registration is impossible to complete, at least the last time I tried.

Yeah and I tried to clear everything I could, but no dice.

Ask HN: How does Quora auto login work?

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