JwtBearerEvents.OnAuthenticationFailed not being called...sometimes - asp.net-core

I have an odd problem. I'm new to JWT authentication so it's probably something I'm doing wrong.
I'm testing out the Refresh Token mechanism and it works sometimes but not others because sometimes the JwtBearerEvents.OnAuthenticationFailed event does not fire.
I'm using C# (.NET 7) to build an ASPNET Core WebAPI.
Essentially:
On log in (via an AJAX call) I create a JWT token (expires after 10 seconds) and a refresh token (expires after 10 days) and send each back to the client in a cookie.
Chrome correctly lists both the JWT token and the Refresh Token cookies.
I make further (valid) GET requests via AJAX to the API methods which process and return successfully.
If I make a request just after (but within a second of) the expiry time of the JWT token then the JWT cookie is sent to the API, fails validation and the OnAuthenticationFailed event fires.
The Refresh Token mechanism does its thing and the JWT token and Refresh Token are successfully refreshed. Chrome shows the updated cookies correctly. All brilliant so far.
I make further (valid) GET requests via AJAX to the API methods which process and return successfully.
But...if I make a request a bit longer after the expiry time of the JWT token (only a second or 2 difference to Step 4.) then the JWT cookie is deleted by Chrome and is not sent, so the token validation never occurs, the OnAuthenticationFailed event DOES NOT fire and the Refresh Token process is never called.
User has to log in again because the Refresh Token mechanism didn't happen.
I guess my question is: Is OnAuthenticationFailed the best way to determine if the JWT token has expired, or is there a more reliable way? I've looked online but can't find any resources to explain this.

Is OnAuthenticationFailed the best way to determine if the JWT token
has expired, or is there a more reliable way?
I think you'd better judge from the expiretime,and there's a claim typed of exp indicates the seconds from 1970-1-1 to your token exp time
after you authoried succeeded,you could try to get the claim type of"exp" from httpcontext
app.Use(async(context,next)=> 
{                
var claims = context.User?.Claims;
var exp = claims.FirstOrDefault(x => x.Type == "exp");
await next.Invoke();            
});
Or you could try to check the claim when you validate the token

I think I've found an alternative way of refreshing the tokens which doesn't require the expired JWT cookie to be sent at all.
I'd followed a tutorial which used the JwtBearerEvents.OnAuthenticationFailed event to capture expiry and, as I'm a bit new to this, had to go through it all with a fine toothcomb to work out why it wasn't working.
The client-side code now responds to the simple 401 NotAuthorized status and that kicks of the process to refresh the token, which only requires the Refresh Token cookie to be sent.
Update: Just in case anyone else is stuck with this, in the case where the JWT cookie is removed by the browser due to expiry and therefore doesn't send it, the OnChallenge JwtBearerEvents event occurs instead of OnAuthenticationFailed.

Related

Authentication + Persistant login with JWT and refresh token

Stack: React, tRPC, Redux Toolkit
So I'm trying to build out my auth in a way that's somewhat secure and can handle persistent logins. The best approach I've found so far is to have a short-lived JWT that authenticates the user, and then a refresh token with a key saved on the DB that allows new short-lived JWTs to be generated. The short lived token would be stored in my Redux store, while the refresh token would be saved as a cookie so it can be used to log in the user when they refresh the page.
So my first question is, is this in general a good way to approach this problem? I see conflicting answers sometimes.
The second problem I'm facing is that if I want to use a refresh token, I'm going to have to check and see if the JWT is not expired before each API call, and if it is, hit the /refresh endpoint and use the new JWT. However, with my current stack, I'm not sure how to do this in away that doesn't involve a lot of copy and paste code.
The only solutions I've been able to think of so far are:
Just include both JWT and refresh token in every API call. Always send back either the same JWT or a new JWT. If the refresh token is expired, send back a 401.
Do something to so that before every thunk is dispatched, check the JWT/refresh token and hit /refresh if needed before dispatching.
I'm sure there's a better way to handle this though. Any pointers?
Are you sure that you need the short-lived JWT in the first place? Maybe all you need is a good-old cookie-based session. In fact, what you describe with how the refresh token would be used + the first proposed solution, is pretty much how you would use a session. Unless there is a real need for short-lived JWTs as access tokens, I would get rid of them.
If you decide to stick to access and refresh tokens, then what you describe in solution 2 is not enough. You always need a way of intercepting a 401 response from the API, which indicates that the access token is expired. You should then refresh the access token and call the API again. If the refresh fails with 401, then you know that the refresh token is expired. The expiration check needs to be done on the backend because only there you are sure of the clock settings. Clients can have their clocks skewed which makes verifying expiration time on the client side useless.

best practices for refreshing access tokens automatically

I'm building a react native app which uses the spotify web api. I'm using the authorization code flow to authorize a user. First I get a authorization code which can be used to obtain an access token and a refresh token. Everything works!
The problem is: an access token is only valid for a limited amount of time. That's where the refresh token comes in. I understand this concept, but I'm breaking my head about how to implement this.
Let's say a users opens the app, requests an access token and uses this for some time. Then, the user closes the app. After 15 minutes, the users opens the app again. The access token has now expired, so I need to request a new access token.
I've come op with several "solutions". Can someone point me to the correct solution?
Solution 1:
Every time the user opens the app, I request a new access token and use this. Problem: when the user uses the app longer than the valid time of the access token, I won't work anymore.
Solution 2:
I use the access token that's stored in the secure storage on every request. When a request comes back with 'access token invalid' (I don't know the exact error code but you guys know what I mean), I request a new access token with the stored refresh token, and then I send the previous command again (with the new access token). But my question here is: can I use some kind of "wrapper function" which checks the response of the request, and if the response is "access token invalid", it automatically requests a new access token and runs the previous request again.
I think certainly correct solution is solution 2,and i think its clear enough.
and for using solution 2 you need somthing like wrapper function,yes its intelligently.
so you should use interceptor:
what is interceptor ?
You can intercept requests or responses before they are handled by then or catch.
in link below there is a good example of implementing refresh token in axios interceptor:
https://gist.github.com/Godofbrowser/bf118322301af3fc334437c683887c5f
I agree that Solution 2 is the best, each time you do a request you can check to see if the Access Token has expired, and if it has then you can request a new Access Token using the Refresh Token as you mentioned and then make your request, in my own project I do this in a FormatRequestHeadersAsync method which calls a CheckAndRenewTokenAsync method where I perform the following check, here shown in C#:
if(AccessToken?.Refresh != null && (AccessToken.Expiration < DateTime.UtcNow))
{
AccessToken = await GetRefreshTokenAsync(
AccessToken.Refresh,
AccessToken.TokenType,
cancellationToken);
}
You can store the Access Token and the Refresh Token and then use something similar to this before you make each request to the API this will refresh your token and then you can store the new Access Token and the existing Refresh Token.

How to handle expired auth tokens in Xamarin MobileServiceClient?

I am using client-flow authentication in Xamarin.Forms and am trying to figure out how to handle when an authentication token expires.
My Code:
Upon initial login, the user logs in with the native Facebook SDK and I pass the access_token to MobileServiceClient to get back an authenticated user.
var user = await client.LoginAsync(MobileServiceAuthenticationProvider.Facebook, token).ConfigureAwait(false);
I then save the user's UserId and MobileServiceAuthenticationToken in local settings (using the Xam.Plugins.Settings plugin).
The next time the user opens the app, I set the user from settings and skip manual login:
if (!string.IsNullOrWhiteSpace(Settings.AuthToken) && !string.IsNullOrWhiteSpace(Settings.UserId))
{
client.CurrentUser = new MobileServiceUser(Settings.UserId);
client.CurrentUser.MobileServiceAuthenticationToken = Settings.AuthToken;
}
My Question:
This works great. However, I know that the MobileServiceAuthenticationToken has an expiration on it. What will happen in my app when the expiration date is reached? How do I refresh the token without requiring the user to re-log-in to Facebook? I have tried the MobileServiceClient's RefreshUserAsync() method, but I get the following exception:
Microsoft.WindowsAzure.MobileServices.MobileServiceInvalidOperationException: Refresh failed with a 400 Bad Request error. The identity provider does not support refresh, or the user is not logged in with sufficient permission.
Is there a way to test this? (since the token expiration is 3 months from now.) Thanks for the help!
Microsoft.WindowsAzure.MobileServices.MobileServiceInvalidOperationException: Refresh failed with a 400 Bad Request error. The identity provider does not support refresh, or the user is not logged in with sufficient permission.
Since you are using client-flow authentication, you could not use RefreshUserAsync() for refreshing the MobileServiceAuthenticationToken. Your mobile backend does not cache the related access_token and refresh_token for renewing the authentication Token.
Is there a way to test this? (since the token expiration is 3 months from now.) Thanks for the help!
AFAIK, the MobileServiceAuthenticationToken expiration is one hour by default, you could use https://jwt.io/ to decode your token and check the exp property, then use https://www.epochconverter.com/ to convert your timestamp to human date.
For your requirement, you could follow adrian hall's blog about Caching Tokens and refer to the IsTokenExpired method for decode your authenticationToken and check the exp, then manually renew the authenticationToken.
Per my understanding, there are two approaches for you to achieve your purpose:
You need to cache the facebook access_token in your mobile client side, after you manually checked the authenticationToken and found that it expired, then you could manually execute the following code for renewing the token and explicitly update your local cache.
var user = await client.LoginAsync(MobileServiceAuthenticationProvider.Facebook, token).ConfigureAwait(false);
Note: Your facebook access_token has the Expiration Date, so if your access_token expired, then you need to force the user to log into Facebook again before acquiring the new authenticationToken.
Or you could build your custom endpoint for refreshing the authenticationToken and explicitly set a long lifetime for your new authenticationToken, details you could follow this similar issue. Note: For your client-side expiration processing, you need to renew the token before your local authenticationToken is about to expire.

Is it necessary to refresh tokens every request?

I'm here because I wasn't satisfied with what I found on google.
I am generally building SPA's, so for me the process was simple: At succesful login generate a jwt and use it for every request I make from the client.
Someone told me that I should refresh that token and send back a new one for every request I make. Does this make sense for me to do? I mean, if someone is trying to hack me, sniffing the requests will give the hacker the same tokens I receive, so what's the catch?
I mean, what if I launch a request before another one is finished? Teoretically I would send the same token twice and one of the requests will be rejected.
How is this correctly handled? I'm sure there is more to this than what I could think myself.
It is a compromise between security and convenience.
No, you don't need to refresh the token on each request. But you definitely want your JWTs to expire at some point. This is to protect you from JWT theft where malicious user could use stolen access token to gain access to target resource indefinitely.
Here is what you can do to handle token expiration:
Implement a refresh token flow. You will issue an access JWT and a refresh JWT when authenticating. Once access JWT has expired you will use refresh JWT to obtain new access JWT.
Implement sliding expiration. After the half of the JWT validity time has expired you would issue a new JWT. An example of it can be found here. I would recommend to include a deadline to when a token can be expired. For example, initial token validity is for 20 minutes and deadline is 8 hours. After 8 hours of sliding expiration you will stop issuing new tokens.

JWT token refresh (sliding sessions) and signout

I am very new to JWT and I ended up inheriting a codebase which makes use of JWT. Now there are some very fundamental problems which I am facing and I am not finding any answers. This question is not code based so please bear with me.
Let us say that my JWT token is valid for 4 hours. Here are my requirements/constraints
If a user is working at 3 hours 59 minutes. their session should get extended by 2 hours and they should not be required to re-enter credentials.
The client side java script must not cache the user credentials in any way.
It is OK to refresh the JWT token with a new one... but you must not do it on every request you make on the server. So the client has to be intelligent to refresh the JWT token when the time is right. You must not try to issue a new token on each and every request you make to the app, because we will end up in a scenario where we have 1000s of active tokens generated within the course of a session and all of them are active. this makes the signout requirement even harder.
Once a user clicks signout. the JWT token should not be usable anymore. Even though its life time is still valid.
If a signout occurs. All tokens which were issued (as part of session extension) should get invalidated. Not just the last one.
I am starting to read about JWT but it seems like my requirements cannot be met with JWT. these requirements are very easy to meet with the session id approach. but I don't want to give up on JWT just yet.
JWT life extension
You can issue a JWT with the old one. Your client app have to request a new JWT when it is close to expiration time. Client knows the expiration time reading the exp claim and can invoke a refresh service to get a new token. If the client app is closed then the JWT will expire and it will be necessary for the user to present the credentials again
Logout
It is recommended to let tokens expire, but you can use a blacklist to store JWT that are still valid but can not be used for authentication:
When user clicks logout
After refreshing a ticket close to expiration time
You will need to add to JWT an unique identifier jti. The blacklist will contain jti and exp. Once current time > exp the entry can be discarded.
See Invalidating client side JWT session