Stop using JWTs

stop-using-jwts.md

Stop using JWTs!

TLDR: JWTs should not be used for keeping your user logged in. They are not designed for this purpose, they are not secure, and there is a much better tool which is designed for it: regular cookie sessions.

If you've got a bit of time to watch a presentation on it, I highly recommend this talk: https://www.youtube.com/watch?v=pYeekwv3vC4 (Note that other topics are largely skimmed over, such as CSRF protection. You should learn about other topics from other sources. Also note that "valid" usecases for JWTs at the end of the video can also be easily handled by other, better, and more secure tools. Specifically, PASETO.)

A related topic: Don't use localStorage (or sessionStorage) for authentication credentials, including JWT tokens: https://www.rdegges.com/2018/please-stop-using-local-storage/

The reason to avoid JWTs comes down to a couple different points:

• The JWT specification is specifically designed only for very short-live tokens (~5 minute or less). Sessions need to have longer lifespans than that.
• "stateless" authentication simply is not feasible in a secure way. You must have some state to handle tokens securely, and if you must have a data store, it's better to just store all the data. Most of this article and the followup it links to describes the specific issues: http://cryto.net/~joepie91/blog/2016/06/13/stop-using-jwt-for-sessions/
  • (Yes, people are doing it, and yes, their applications are flawed, and you should not repeat that mistake.)
• JWTs which just store a simple session token are inefficient and less flexible than a regular session cookie, and don't gain you any advantage.
• The JWT specification itself is not trusted by security experts. This should preclude all usage of them for anything related to security and authentication. The original spec specifically made it possible to create fake tokens, and is likely to contain other mistakes. This article delves deeper into the problems with the JWT (family) specification.

Rebuttals

But Google uses JWTs! Google does not use JWTs for user sessions in the browser. They use regular cookie sessions. JWTs are used purely as Single Sign On transports so that your login session on one server or host can be transferred to a session on another server or host. This is within the reasonable usecases for JWTs, and Google has the resources (security experts) to create and maintain a more secure JWT implementation. Their JWTs are effectively not the same as anyone else's.

But stateless is better! You can't securely have truly stateless authentication without having massive resources, see the cryto.net link above. Also, Stateless is a lie.

I don't know how to setup sessions! You don't regularly see articles explaining sessions because the technology isn't particularly new. You also shouldn't need third party information for setup. A session implementation's documentation should take you through the setup process by itself. Almost any web server framework will contain an implementation for sessions, and usually it's very easy to enable if it isn't enabled by default. Express and other Node.js frameworks are somewhat exceptions to this rule, primarily because they are highly modular and single purpose. For Express, you simply use the express-session middleware and a store connector which works with your store (I recommend connect-session-knex, to be used with Postgres, MySQL, or possibly SQLite).

Short term tokens

If you do need a short-lived, signed token for something, there is a better spec called PASETO which is designed to be secure. Just make sure you aren't using them for sessions.

How sessions work

I recommend checking out this gist by joepie91 to learn more how sessions work.

Thanks for info samsch 🙏, the video by R Degges is 🔥 JWT 0 - 100 Session 😉

hello im new to spring security. and with spring boot 3 just being released. is there any example code base to look at with a restful api? thank you

Thank you for sharing this article. And here's the reason for Google does not use JWTs for user sessions in the browser. They use regular cookie sessions on its Security section

For example, cookies called ‘SID’ and ‘HSID’ contain digitally signed and encrypted records of a user’s Google Account ID and most recent sign-in time. The combination of these cookies allows Google to block many types of attack, such as attempts to steal the content of forms submitted in Google services.

As far as I can remember I stopped using sessions because it was hard to scale. clustering your webserver is cumbersome even when you are lucky enough that your webserver implements it right that's why the extra layer of complexity of adding a distributed cache is required in large scale app. I prefer to use Hazelcast or Redis.

Cookie sessions and local storage also have their own downsides.

You don't have to put sensitive info in JWT. You can put an identifier / user id in a JWT token and retrieve those data from cache by using that identifier.

I wouldn't say Stop using JWT, I would say use it in a right way.

@omidp Refer here: http://cryto.net/%7Ejoepie91/blog/2016/06/19/stop-using-jwt-for-sessions-part-2-why-your-solution-doesnt-work/

If you can retrieve your user from the cache, you can retrieve a session for the same (probably cheaper, actually) "cost".

There is no right way to use JWTs for sessions. Like, it's not an opinion, it can be objectively and logically shown.

funny how cryto.net is over http :)