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Aren’t JWT tokens only supposed to be good for 10-15 minutes? I know using flask-jwt you have to go out of your way to make them last longer than that and it i

Aren’t JWT tokens only supposed to be good for 10-15 minutes? I know using flask-jwt you have to go out of your way to make them last longer than that and it isn’t recommended.

Grimm1 5y ago
Yes but a lot of times people don't do that properly, some frameworks have incorrect defaults or people don't want to deal with writing the logic to handle refreshing tokens after that 10-15 minute window etc etc. They are insecure but it's not a problem if you follow best practices like those, the difficulty is a lot of people don't because they don't really understand what it is they're doing or potentially causing by making the changes that let them be lazy or do things the easy way. You could probably change the title to articles like this from "JWT Tokens are NOT safe" to "JWT Tokens are NOT safe when you ignore all security practices and take the easy way out" but that doesn't make for a flashy title.
lstamour 5y ago
I know some folks who thought they could use JWTs from a traditional LDAP identity vendor (open source Active Directory so you can manage computer login credentials centrally, issue Kerberos tokens, etc.) but they managed to misconfigure their JWTs by following the defaults from the vendor so the JWTs issued were valid forever. When I tried to explain that they couldn’t be revoked without key rotation, I got some very blank looks. I’m not even sure the tokens had an iat (issued at timestamp) though if they did you could use that to at least ignore tokens older than a certain date. They assumed because they deleted the cookie at logout, it wouldn’t matter that the session could be re-used forever. Then they implemented session limits by setting a cookie expiry time. /face-palm Issuing your own JWTs also means you have to keep the secret or certificate used to sign them secure or if it leaks anyone could impersonate anyone else. This is especially problematic if admin or role assignment is embedded in the JWT.
lstamour 5y ago
Expiry is just one of the fields you can set. Also if you’re curious about what’s inside a JWT, the next time you see one from an OAuth cookie perhaps, copy and paste it into a tool like https://JWT.ms https://JWT.ms run by Microsoft and it can show you the details. Commonly you want to load a JWKS (with multiple keys possible for easy revocation) to validate the signature, and check the iss (issuer of the JWT), aud (your app registration or audience of the token) and expiry date of the token. Oh and don’t forget to hard-code or reference the JWKS validation method so you don’t accidentally allow “none”. JWTs are not without their complexity, but the same could be said about maintaining secure session cookies and implementing 2FA yourself perhaps.

Aren’t JWT tokens only supposed to be good for 10-15 minutes? I know using flask-jwt you have to go out of your way to make them last longer than that and it isn’t recommended.

Grimm1 5y ago

Yes but a lot of times people don't do that properly, some frameworks have incorrect defaults or people don't want to deal with writing the logic to handle refreshing tokens after that 10-15 minute window etc etc. They are insecure but it's not a problem if you follow best practices like those, the difficulty is a lot of people don't because they don't really understand what it is they're doing or potentially causing by making the changes that let them be lazy or do things the easy way. You could probably change the title to articles like this from "JWT Tokens are NOT safe" to "JWT Tokens are NOT safe when you ignore all security practices and take the easy way out" but that doesn't make for a flashy title.

lstamour 5y ago

I know some folks who thought they could use JWTs from a traditional LDAP identity vendor (open source Active Directory so you can manage computer login credentials centrally, issue Kerberos tokens, etc.) but they managed to misconfigure their JWTs by following the defaults from the vendor so the JWTs issued were valid forever. When I tried to explain that they couldn’t be revoked without key rotation, I got some very blank looks. I’m not even sure the tokens had an iat (issued at timestamp) though if they did you could use that to at least ignore tokens older than a certain date. They assumed because they deleted the cookie at logout, it wouldn’t matter that the session could be re-used forever. Then they implemented session limits by setting a cookie expiry time. /face-palm Issuing your own JWTs also means you have to keep the secret or certificate used to sign them secure or if it leaks anyone could impersonate anyone else. This is especially problematic if admin or role assignment is embedded in the JWT.

lstamour 5y ago

Expiry is just one of the fields you can set. Also if you’re curious about what’s inside a JWT, the next time you see one from an OAuth cookie perhaps, copy and paste it into a tool like https://JWT.ms https://JWT.ms run by Microsoft and it can show you the details. Commonly you want to load a JWKS (with multiple keys possible for easy revocation) to validate the signature, and check the iss (issuer of the JWT), aud (your app registration or audience of the token) and expiry date of the token. Oh and don’t forget to hard-code or reference the JWKS validation method so you don’t accidentally allow “none”. JWTs are not without their complexity, but the same could be said about maintaining secure session cookies and implementing 2FA yourself perhaps.