I have developed a simple bakend server in node with jwt authentication, but I still have a question: after the user has correctly logged in and saved the token in the client side should the server validate the token at every user request? For example when accessing the /profile route (which takes the user to the profile page), or when for example the user creates a question by sending a post request to /posts/create route should I use the method jwt.verify(...) to check if the token is correct everytime? Is it correct also to send the jwt access token instead of the refresh token or is this a bad practice?
Yes, you should validate each request. That is call middleware. In the first step, you check authentication. After that, you can use it for authorization. You can write role, some permission, or other info in JWT.
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I am working on an authentication system, implemented the front end using vuejs and back end with nodejs. User is able to register and login successfully. I am verifying user is logged in using jwt token. My problem is anyone can login by manipulating the localStorage jwt token value. Is there anyway to prevent it.
You should be using an asymmetric signature on your JWT token, and the private key should be available only to the server that creates the JWT. If this is the case, then it's highly unlikely that a user would be able to forge JWT claims.
Here's a step by step of how your server should prevent someone from changing their JWT info:
Your NodeJS server creates a new JWT using an encryption key (we'll call it secret-key) to create the signature, and it sends the token to the client.
The user decides they want admin access, so they change their permissions in their local JWT and send it to the server.
The NodeJS server re-signs the header and payload of the user's JWT using secret-key and compares that generated signature with the signature in the user's JWT. If they match, then nothing has changed about the user's JWT. If they don't match, then either the user changed something in the header or payload, or they tried re-signing the token with their own encryption key. Either way, your server can tell that the JWT isn't valid, and you can deny them access.
I have a Keycloak server setup with a realm and a client. I have Authorization setup on the client and I'm able to evaluate the authentication within the admin interface.
When I click "Show authorization data", I can see in the response an authorization attribute with permissions.
I have a web client that uses a redirect via keycloak for oidc authentication. I would like to limit which keyclock users are able to login into the client, so I would like to authorise the login, but I'm unable to see the authorization attribute in the JWT.
Am I completely misunderstanding how this works, or is there something I can do to see that attribute?
OK, I've finally go my head around it. Short answer - I needed to RTFM.
Long answer - I needed to hit the token endpoint twice. The first time with grant_type = authorization_code to get the access token. Then again with grant_type = urn:ietf:params:oauth:grant-type:uma-ticket (and with the access token in the header) to get the keycloak client to authenticate.
If the second response comes back as 403 - access_denied, then I reject the login, otherwise, I allow the user to login into my system.
The specific bit I needed can be found in the docs is here: https://www.keycloak.org/docs/6.0/authorization_services/#_service_obtaining_permissions
I'm making a login page and I've found that JWT tokens are preferred over sessions but I don't understand what to do with a token.
I send user and password uncrypted with ajax to server and validate the user in a php file which then returns a JWT.
What should I put in my JWT? Do I only check for a token to know if the user is logged in or do I process it somehow to check if it's the right token? If so, how?
So far I've seen examples on client side where you only check if token exists but why should I have hashed data as token instead of a 1 or a 0. I don't get the advantages of this method.
EDIT: Should I both request a JWT token which I store in session storage and store what the user types in the log in field also in session storage and then compare them with eachother every time the user reloads the page?
Looks like we need basics of how JWT works here:
The client sends username/password to the server using ajax.
The server checks username/password and if they are valid, creates an encrypted token, which the only server can read and understand.
Server takes into account various fields (also known as "Claims") like "iss" (token issuer) and "Sub" (Subject of token), whole list here.
We can custom fields like user-id which can be used later while validating token.
Server sends token back to client through response. Client saves this token in local storage or some variable.
With each further request, client sends this token as header.
Server examines and validates this token, gets require info from this token like user-id and responds to the user appropriately if valid. Token may also contain expiry date/time, so after a certain time, the server may choose to refuse to serve a client.
While this may not directly answer your question, it clarifies basic workflow of GWT.
My Question is that I was Implemented JWT Token When User is logged In. Also Done some test Through POSTMAN. Getting token when User is validating with username and password. Now My API is completed and whenever Front-end Guy needs API Calls, He have to pass JWT token. Now This token is visible on AJAX API call. Is there any way that I can Hide all token so that Attacker won't get this token?
jwt is not secured by default.
first if you want to work with jwt in your website,it must work on https.
second if you store it on a cookie use the cookie http only option to prevent javascript cookie hijack
also you can use jwt in OAuth for more features
I have tried implementing JWT to my Angularjs application for a secured authentication. I have generated the JWT at server side(java) and the implementation returns a JWT to the client side after a successful login. I have stored the JWT in $http.defaults.headers.common.Authorization and also in the $window.sessionStorage. Now I could see the JWT in all all requests made by the $http service.
The part I am not clear is I dont know how to proceed from this point. What I guess is I should validate the JWT from now on for all $http calls at the server side somehow. Can someone clarify me how I should proceed for validating the client side JWT at the server side ?
Yes every time the client makes a request to the backend, you now have to supply the JWT in the header.
Inside the JWT you can have some parameters that identifies the user, like his username for example. Do not store password or other sensitive information inside the JWT.
If you are useing Java, you could create a Filter that will be mapped to a url that only an authorized user can have acces. In the filter you can make the necessary checks to see if the suplied token is correct, if it is you can let the request pass trough, otherwise you can return to the client an error specifying that he does not have access.
If you need more information, may be this is a good place to start.