Managing a Secure JSON Web Token Implementation

Now, what is the (currently accepted) best way to store that refresh token in a ReactJS frontend? I send the JWT via Cookies as “httpOnly; Secure”, would the refresh token go the same route? If so, wouldn’t compromising of the JWT also mean the same for the refresh token? And therefore give the person unlimited access until key-rotation?

Or, like with Oauth2, is the idea that JWT gets transmitted back to the server with every request, and the refresh token only when needed and therefore having a slightly smaller risk of intercepting both keys (assuming the refresh token is not stored in cookies)?

You should not store any token in the frontend. Instead, have a server doing that and use a classic secure cookie session. The session is bound to the token / refresh token and can then do the token management.

Alternatively, don't use access token / refresh token but an ID token. The refresh of the token will be done via the ID token and the user's session (cookie) to the OAuth provider.

As long as all supposed consumers of JWT are on my infrastructure I prefer to make all tokens revokable. Tokens TTL is smaller than 1 hour so I keep 1 hour worth of revocations on all servers (pushed via queue). If key is on list it is refused (without database hits)

If you are going to use JWT besides its failings, you should use it safely. But not all advice in this piece is equally strong.

1. RS256 vs ES256 - you shouldn't use either. RS256 not just an old standard on the way out. With safe keys sizes tokens are often going to be too large and signing too slow for you. ES256 on the other hand, suffers from many theoretical flaws and at least one practical flaw that (complete breakdown if nonce is reused) that helped jailbreak the PS3.

The only reasonable asymmetric signature algorithms implemented for JWT are Ed25519 and Ed448, but they are still not supported by most libraries.

2. Key IDs - always include them, even if you're just using 1 key for now. Otherwise you cannot rotate keys securely without having to reject all existing tokens.

3. Have relatively short lifetimes for JWTs if you're not using a blacklist. A token that lasts for 180 days with no possible way to revoke it is a dangerous little thing.

4. Always verify that you only accept JWTs signed by the algorithm you're expecting. Otherwise you might be fooled by a JWT signed with HMAC-SHA256 by your RSA public key (which is known to the attacker: https://auth0.com/blog/critical-vulnerabilities-in-json-web-...

5. Under no circumstances accept tokens signed with "none". The standard is just bonkers.

6. Rotate keys every month if you can, not every 2 years. This is keeping your joints well-oiled.

7. Damage control is still possible when using JSON Web Signature (JWS). JSON Web Encryption (JWE), on the other hand, is just a train wreck that is very hard t ouse properly. Avoid it all costs. PASETO provides a viable alternative for most cases it makes sense to use an encrypted token.

8. If you can avoid JWT, just avoid it. It's just too hard to implement securely. In the past there weren't any widespread alternatives, but PASETO is supported in most common platforms now and is clearly a better option.

https://paragonie.com/blog/2017/03/jwt-json-web-tokens-is-ba...

From the article, refresh tokens are revokable. The whole point of JWT + refresh token is that for normal operation, you don't need to hit the database but still able to revoke a token.