What's the best way to do authentication in modern applications
neciudan.dev
neciudan.dev
As an old guy reading this I had a lot of wtf moments during the setup. Then I laughed pretty hard when we eventually got to this line. Like there's a reason we invented cookies and all mature web frameworks use them for auth.
Cookie stealers, issues with third-party cookies and tracking... it's not like the past was a paradise, in fact, quite the opposite. Hell I 'member times when we had to append ?PHPSESSID=... to URLs. Cookies were a stopgap...
Much more importantly however, is that the cookie standards are a mess! The complexity of cookie default behaviour, their flags, scopes, differences in their SOP (cookies ignore ports for example, so https://example.com:443 and https://example.com:8443 share their cookies) are huge. Research papers have been written in this. And don't even get started on differentials between browsing engines.
This huge complexity of cookies opens up a whole class of authentication attacks where bad (or just weirdly) configured cookies can be stolen cross origin.
localStorage on the other hand is practically impossible to get wrong.
But they're still the superior choice for authN on the web, because if you want to, you CAN configure cookies to be secure. Yes, attackers can ride the session, but it's dependent on the user being on the tab and you being able to consistently execute JS. Client-side compromise (ie attacker controls the entire browser) is not feasible to defend against anyway.
The main issue with JWT+localStorage is you can actually execute one-off JS, exfiltrate the token and come back later. I've _never_ seen a well-executed JWT+localStorage implementation in 10 or so years, because teams inevitably realise they can't reliably revoke sessions (another advantage of cookies) and then start giving out long-lived access tokens but adding them to the database. Or some variation of that.
Instead of speculating, I'll ask: what does this mean?
It's my understnading that setting up cookies to work on mobile is quite painful, though it depends on the platform. IIRC iOS has gotten better at it with a shared cookie storage, but Android requests are still stateless by default, so you basically have to manually wire up a cookie jar and carry it around everywhere you go, so to speak.
Attributes like SameSite also behave differently, and WebViews don't share the same cookie jar as native requests as far as I understand.
Bottom line is that maybe "Cookies also don't work on mobile" is a bit of a wrong statement, but it's certainly more of a hassle and a path lined with more footguns than just wiring up an OAuth provider and sending access and refresh tokens back and forth using Authorization headers. The great thing with Session cookies on desktop is simplicity, which you sort of lack on mobile.
This is what aspnet core does by default if you enable cookie-based authentication. Gives you the best of both worlds.
My experience with "AI" is that if you ask the right questions in the right way (and give it access to accurate information to build it's answers from) it's actually really good at explaining things "quite clearly".
Is there someone in another part of the world that would like hacking you only if you’re not using httpOnly cookies, happy to know that you used localstorage?
I really want this era of AI generated writing that reads so poorly to end. Or at least society should be ashamed of publishing this content.