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you cant generally reuse cookies across domains, because browser controls which domain receive which cookie. Also cookies are not cryptographically signed and t

by slt2021 1y ago

you cant generally reuse cookies across domains, because browser controls which domain receive which cookie. Also cookies are not cryptographically signed and thus easily forgeable by the client/browser. JWTs on the other hand allow to be used across domain, so that you can use JWT issued by your IDP on one domain, to be trusted on another domain. crypto signature helps in verifying integrity of data. sessions are usually tied to a single backend/application server. Its hard to reuse a session data across different apps. JWTs on the other hand allow sharing session data across different app servers/microservices.

gerdesj 1y ago
"Also cookies are not cryptographically signed and thus easily forgeable by the client/browser." My Apache webby thingies quite happily dole out encrypted cookies: https://httpd.apache.org/docs/2.4/mod/mod_session_crypto.html https://httpd.apache.org/docs/2.4/mod/mod_session_crypto.htm... Your notes on cross site issues are also described there. JWTs are mutually shared secret passable with nobs on - you can store loads of data in them. Cookies are more one shot and one piece of data.
- formerly_proven 1y ago
  Encryption generally doesn’t provide authentication, so I wouldn’t be surprised if that Apache module allows a user to flip is_admin=0 to 1 because the encryption is sufficiently malleable to do that. Especially because that page mentions 3DES.
kevlened 1y ago
> Also cookies are not cryptographically signed and thus easily forgeable by the client/browser While it's true that you could avoid signing cookies, this isn't the default for any server library I'm aware of. If your library doesn't require a secret to use for signing, you should report it. I'm also unaware of JWT libraries that default to "none" for the algorithm (some go against the spec and avoid it entirely), though it's possible to use JWTs insecurely.

gerdesj 1y ago

"Also cookies are not cryptographically signed and thus easily forgeable by the client/browser." My Apache webby thingies quite happily dole out encrypted cookies: https://httpd.apache.org/docs/2.4/mod/mod_session_crypto.html https://httpd.apache.org/docs/2.4/mod/mod_session_crypto.htm... Your notes on cross site issues are also described there. JWTs are mutually shared secret passable with nobs on - you can store loads of data in them. Cookies are more one shot and one piece of data.

formerly_proven 1y ago
Encryption generally doesn’t provide authentication, so I wouldn’t be surprised if that Apache module allows a user to flip is_admin=0 to 1 because the encryption is sufficiently malleable to do that. Especially because that page mentions 3DES.

kevlened 1y ago

> Also cookies are not cryptographically signed and thus easily forgeable by the client/browser While it's true that you could avoid signing cookies, this isn't the default for any server library I'm aware of. If your library doesn't require a secret to use for signing, you should report it. I'm also unaware of JWT libraries that default to "none" for the algorithm (some go against the spec and avoid it entirely), though it's possible to use JWTs insecurely.