JWT Token Validation in Angular - node.js

I wrote Local Authentication Logic in Node, Generated a JWT and will send it to Angular App on Login.
In Angular, As soon as user Logs in with Correct Credentials, I then set the JWT in Local Storage!
In Angular I just check whether there is token in localStorage upon different route navigations. But how do I validate the token ??
If Iam changing the token from 'xxxxxxxxxxxx' to 'yyyyy' even then it's working since I am just checking whether there is token available in Local Storage.
How do I overcome this issue. ?
I knew about Headers. But those work only for API Calls, I simply want to restrict the user entering into protected Frontend Pages with invalid token.

Related

Should i logout a user if access token is malformed?

I am creating a Node js / Express js based, login registration system using JWT (i am using JSONWEBTOKEN npm library).
Whenever a user login, that user gets a pair of access and refresh token. Now for accessing resources user need to send access token to backend.
Now when i verify the access token send by user to backend and if it will not get verified then it produces three types of error (as mentioned is JSONWEBTOKEN library in npm):
Token Expired Error: If i get this error, then in that case i will send response to frontend to send the request to refresh token route to get a new pair of access and refresh token.
JsonWebTokenError: If i get this error then it means that access token is malformed. Then in this case what should i do? Should i logout a user or should i will send a response to frontend to send request to refresh token route to get a new pair of access and refresh token. <-- This is the main question should i logout a user?
NotBeforeError: Since i am not using nbf claim and then in that case i dont need to worry about it.
Please provide your useful suggestion. while building backend security plays an important role.
This is useful to read: JWT refresh token flow.
Talking short, you should logout user if refresh token malformed or expired.
According to JWT idea, access token is short-life token. When it doesn't pass validation due to malformed or expired you have to send refresh token to server to get new pair. User continues to work using new access token without interruption.
If JWT is malformed then just block that call by responding with 403. that's fine. The application then takes the decision on it to refresh the token or not.
When a user logs out please revoke the issued token even if it is a JWT.
JWT also needs to be revoked as best practice. Yes, JWTs are self tokens and expirations already part of themselves. But if user logs out and still their JWTs are not expired means someone can use that token to call different APIs. So it is a security breach.
To avoid such things we should maintain JTI claim of that JWT in our backend with the same TTL with the value of JWT "exp". When the user logs out we have to clear those JTIs and notifcy the API callers about this just putting into some event service from their API Gateways should get to be notified and clear their side cached tokens if anything and cross check with identity system (Introspection).
This is we have to design the system to avoid further security related issues.
First thing is that user will be logged out from front end side.
front end will send request to your node server and token will be verified. Server will only send the response that token is expired or malformed and based on that front end will perform the action.
If token is expired then request for new token.
Is token is malformed then based on your requirements you can show results to your end user. You can either logout user or you can show unauthorized page too.
Suppose, you have role based website and some unauthorized user is trying to access root level routes then you can show unauthorized page.

Regenerate auth token

I have a flutter app with a node.js backend api. I'm using firebase Auth for authentication. The way it works now (which I don't know is standard,) is the user sends a request to firebase auth to login/signup. The jwt gets stored in the flutter app, then it sends that firebase jwt to my API, which verifies it's a valid token firebase.auth().verifyIdToken(), and my API sends over a new jwt created with firebase firebase.auth().createCustomToken(...) with custom info.
Before every response my API sends over, it checks if the custom jwt was created after 15 min. If it was, it recreates a new custom jwt. If it passed 7 days since it's original creation, it logs out the user.
The problem is, I don't see a way to regenerate a firebase auth token on the server. Which means every hour the user will have to re-login.
I feel I'm overcomplicating things, but I'm not sure of a better design of doing this. Is there a standard? How can I make this better and how can I make it that the user doesn't have to re-login after just 60 min?
The custom tokens created by createCustomToken() are used when you have a third party auth system but you want to login your users with Firebase auth.
The problem is, I don't see a way to regenerate a firebase auth token on the server. Which means every hour the user will have to re-login.
You don't have to do anything on the server. Every time you need to call your API, you can use getIdToken() to get user's ID token.
var token = await FirebaseAuth.instance.currentUser().getIdToken();
This will return user's current token and if it has expired then it'll a refreshed token. You can then pass the result to your API. There's no need to explicitly store the token anywhere yourself.
Whenever you are making an API request, the flow could be as simple as:
Get user's ID Token using getIdToken()
Pass this token in your API request
Verify it using verifyIdToken() and return the response.

Node.js JWT token isn't get passed to another page

First of all sorry if this subject already exists. I have problem with jwt token. I got register/login system in nodejs with mongodb. After I login (at localhost:3000/auth/login), my token is generated, but when i try to access another page (ex. localhost:3000/priv) it responds access denied. It look like the token has to pass with new request to another page, but how?
Jwt token doesn't work like cookies in the browser
You've to manually store the token to the localStorage or other storage in frontend after login & then attach that jwt token accessing from localStorage to Authorization header while requesting to another route
You can learn this entire process from https://auth0.com. They've a great tutorial on it. Also learn about access-token & refresh-token mechanism to ensure better security

How can I use azure ad access token which is got from SPA to protect backend api?

I want to use azure AD as authentication.
If user who is in certain organization logged in from SPA, and give access token to backend, then I want to permit access from SPA.
So, I want to check if token passed from SPA is valid or not.
How can I do this?, Or Can I do this?
I want to build backend server with node.js app, and deploy backend app to app service or Azure Container Registry.
I think bearerStrategy would work.
Ref https://github.com/AzureAD/passport-azure-ad
BearerStrategy uses Bearer Token protocol to protect web resource/api.
It works in the following manner: User sends a request to the
protected web api which contains an access_token in either the
authorization header or body. Passport extracts and validates the
access_token, and propagates the claims in access_token to the verify
callback and let the framework finish the remaining authentication
procedure. On successful authentication, passport adds the user
information to req.user and passes it to the next middleware, which is
usually the business logic of the web resource/api. In case of error,
passport sends back an unauthorized response.
In the past, there was an ADAL version for node apps. I don't know if it's still valid or not, but here are useful links:
https://medium.com/#liangjunjiang/verify-and-decode-azure-activity-directory-token-bc72cf7010bc
https://learn.microsoft.com/en-us/azure/active-directory/develop/authentication-flows-app-scenarios

Check if user logged in from backend Firebase Authentication

In my frontend, the user logs in using Firebase Authentication Browser. That part works perfectly fine. In addition to Firebase backend, I also have NodeJS backend that serves additional content. However, I need to serve the content to only Authenticated user.
My question is: Is there a way for my NodeJS backend to know that a user has been authenticated when they make a request?
An authenticated client is issued an ID token that uniquely identifies the user. The client can get this this token using the provided API. Then, it can pass that token to external APIs, which is verify the token using the Admin SDK.

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