what is the best practices to handling JWT in server side
1) I saw lots of code.they are maintained in database .is it good practice?
2) can we maintain as session value?
How we should implement JWT in server side in spring boot
No. The whole point of a JWT is to contain everything in the JWT itself to be able to identify the user. There is no reason to store a JWT at server-side (unless you want to somehow maintain a list of blacklisted/revoked JWTs, but even then, an ID or something inside the JWT should be sufficient).
No. The whole point of a JWT is to contain everything in the JWT itself to be able to identify the user. And this is precisely what allows avoiding sessions, and to be completely stateless: you receive the JWT, and if you know the secret key used to sign it, you can know who the user is, and be sure the JWT hasn't been counterfeited.
I think you need to understand what a JWT is, and how they work. Why do you want to store JWTs?
Related
We decided to switch from Basic-Auth to JWT because of the session-ids that were stored in the memory and which leads sometimes to over-memory consumption in shoot-down of our Spring-Boot server that serves an Android mobile app like Twitter.
But we have some questions about JWT for our mobile use-case:
How long should an access token lives ?
How long should the refresh token lives ?
How to logout a User by invalidating his access-token and refresh token ? (For the logout we already delete the tokens on the mobile app side, but what if the tokens have being stolen by somebody and are still valid ?)
I will try to answer your queries
How long should an access token live?
You can easily configure expiry time so it depends on your requirement.
In general, try to keep it short.
How long should the refresh token live?
Above goes for refresh token with a condition that refresh token generally lives longer than access token for obvious reasons.
How to logout a User by invalidating his access-token and refresh token?
This part can be a little tricky.
You cannot manually expire a token after it has been created. So, you cannot log out with JWT on the server-side, as you do with sessions.
Can implement a few options like
When a user performs logout action or compromised. Have a blacklist which stores invalid tokens until their initial expiry date. You will need to lookup DB for every request but storage should be less as you will be storing tokens that were between logout & expiry time. You can make the blacklist efficient by keeping it in memory instead of DB.
Store Client IP Address in the claims objects JWT. When validating the token you can check with this client's IP address if it is the same source or not. You can refine it based on need like use User-Agent along with Client IP.
Worst of all reset user credentials or JWT token components to generate a new one which automatically invalidates all existing ones.
Adding a few links for more in-depth detail
Invalidate JWT Token
Destroy JWT Token
I mean it looks more like you should just be using sessions.
JWTs are not a simple replacement. They have a specific function and for some reason they have become embedded as some sort of automatic go to for any auth system.
From what you have described (the lifting of a basic auth to a more secure and modern auth system) you should be using sessions.
Good ol' Cookie sessions.
I'd go in to why more but to sum up:
A) You can control the session without odd stick on "banlist" tables and extra architecture for the JWTs for users that are banned/logged out for a system that doesn't actually need these if you just used traditional cookie based sessions.
B) They are tried and tested and the browser will keep them safe! Session cookies can be made "secure" and "http-only". There are many odd places people put JWTs including the local/session storage of a browser just waiting for a naughty js injected advert to suck them up. JWTs,just like SessionIDs, should
be in an Http-Only, Secure and Same-Site strict Cookie.
So you may as well just use a session ID and get on with life without strange front end state management when the browser is quite happy and doing that securely for you when using a Session Cookie.
C) Traditional sessions are easy to implement. Harder to understand how/why they work with all the SameSite/HttpOnly/CORS/Secure parts going on...but to implement when once understood is 99x easier and require less code when there is the Spring Framework already doing that 99% for you.
I mean sure it isn't hard to write your own JWTAuthTokenAuthFilter and implement a JWTAuthenticationProvider and a JWTCreationService and a `JWTAutoRefreshFilter...and whatever else you dream of...but why bother if you just need a session. Spring does it in like 20 lines of well tested code.
To sum up:
I mean of course properly implemented JWTs are secure...it is just maybe they are not always the best fit tool for a job.
Have a read of:
Stop Using JWTs for Sessions
Of course JWTs have a use. They are for letting a 3rd party know "yes, this is someone I know" before the client hits their API end points. Or for say having one of your servers talk to another of yours...or having client's servers talk to yours or even your servers talk to another companies:
JWT Auth - Best Practices
I am looking for the best approach to work with the IdentityServer4 autorization code flow.
My apps system is quite ordinary: I have an MVC client, a WebAPI and the IS. I also use AJAX to request the API from the client side. So I need the access token on the client side to put it into the authorization header.
Is it good idea to store access token in the cookies?
Do I need self-contained or reference token (it is about security, I suppose)?
What is the best approach to renew when it was expired?
I thought about the two strategies:
Update access token when the first 401 status code was recieved. Can be the problem cause I send more than 1 query to the API and I need to synchronized them and recall the first one (to get result);
Every time before API calling call the MVC client method with GetTokenAsync, check the expire time and get or update and get access token. Seems cheating, cause I need to call the MVC client every time when I want to call the API.
Could you help me to find the best way?
"Is it good idea to store access token in the cookies?"
No, not with the authorization code flow. If you are using an MVC web application you should find a way to store tokens in some kind of datastore away from the browser. All the MVC application should administer is a cookie to access future MVC endpoints (that will make subsequent calls to Identity Server with the appropriate access token in the datastore).
"Do I need self-contained or reference token (it is about security, I suppose)?"
That's all up to you and what you think is best for your use cases. If you'd like to see the information in the access token and skip the extra backend call for validation then use reference tokens. Strategy 2 requires you to use self-contained tokens so that you can check the expiry.
"Could you help me to find the best way?
I don't know if I can give the "best" way, but I'd probably go with strategy 2 and use self-contained tokens.
EDIT: If you wanted to use "axios , to get data from the API" then I would suggest using the implicit flow which has no concept of a refresh token. In this case, leaving it in the cookie should be OK.
Say a user logged in multiple times from different devices, and then they decide they want to logout of device a, we have no way of deleting the JWT which was provided to that device right?
Here is what I've implemented, I'm not sure if this is how other sites do it or if it's a decent way of doing it.
User logs in
I create a redis session token, which has the userId + device name associated to it
I store this redis token as the subject of the JWT
I pass back the JWT.
Now that the user has a JWT, they can now access secured api endpoints. Lets say the user wanted to remove this session, here is what I've done.
User fetches * redis session tokens for the particular userId (of course they need a valid jwt to fetch this data)
They choose the redis session token which they want to destroy.
They send that token to a /destroy/{token} endpoint
The jwt which uses that has that token as the subject will not work anymore.
Doing it this way means on each request, I'll have to decompile the jwt, grab the redis token, and see if it still exists. I guess this isn't expensive todo at all using redis, or any other in memory DB.
Is this a solid/efficient way of doing this? Are there any better/easier ways of doing this?
While implementing JWT authentication/authorization in several apps I also had this same question and reached the same solution if not a very similar one:
In my case, I would store the JWT + UserID + DeviceName in the database, and then I would have an HTTP Request
DELETE /logout/DeviceName with a header Authorization: JWTGoesHere.
This gives me two benefits:
I can now logout a user from any device using a valid JWT (it does not need to be exactly the same JWT, it only needs to be a JWT for that user).
Makes possible the implementation of "Logout all sessions except this one".
In terms of speed, the applications we've developed receive hundreds of requests per second.
More than 90% of these requests need to be authorized, which means checking that the JWT is syntactically valid, checking existence against the database and last but not least check if it's expired.
All these checks (using Redis as the database) take less than 10ms.
Bottom line is: Benchmark it, and if it doesn't take really long then it doesn't need any optimization.
Hope it helps!
If I'm implementing an authentication layer in my app using a mix of JWT and Redis to store session data, do I need to include an expiring in the JWT token itself?
For example, when you login to the app, a session id is generated and added to the redis database with an expiry of 3 days. Then that session id (along with username) is used to create the JWT payload. On all auth requests, I make sure the session id from the token exists in the redis database. If it doesn't, the session has expired and I issue a new token.
Are there security issues with this implementation?
No security issues but one may argue that by including an expiry field in the JWT, the Redis layer can be made obsolete. In principle the JWT allows the application to become stateless. If your application is going to store all of its session data in Redis anyhow (because the JWT would be too large for that) one may argue that the benefit of using a JWT over a plain random session identifier is gone.
Bottom line: the exp field in a JWT is optional and you are free to implement another mechanism to achieve the same.
It depends on how you implement your authentication/authorization layer.
Your authentication/authorization flow is stateful, thus expiration is very coupled with the session. I would include expiration just to let consumers of the whole JWT know when is going to expire and take actions based on this information.
There's also the stateless approach where there's no session identifier and there's no server storing information, but the JWT is self-descriptive, containing expiration and other data as claims. Since the consumer of the JWT relies in the JWT producer, and communications are secured by using a transport-level security approach like HTTPS/SSL, there's no need to maintain state but the state is the JWT itself.
One of most well-known and standarized autentication/authorization flows is OAuth2. I would say that you should build your security layer on top of industry standards. This is good because you avoid a lot of R&D, security holes and time.
I have been reading about JWT.
But from what I read it is not an authentication mechanism but more like a crucial component in a Authentication mechanism.
I have currently implemented a solution which works, but it was just to try out JWT and see how it works. But what I am after now is how one should make use of it. From my experience of it its basically just an encryption mechanism that gives you a unique encrypted key. You are also able to put information inside of this token.
I am wanting to implement it in terms on a ASP.NET web api 2 to be consumed by a mobile application.
So step 1:
app => Server : Login (user, pasword)
Server => app : Login OK, heres your JWT
app => server : Get my profile (sends JWT with request)
Server then decrypts JWT and determines the requests Identity.
Now this is just my understanding of it, Look I could be on the totally wrong path.
Is the Ideal of JWT so that you dont have to authenticate on every request? I just authenticate the users credentials once (on the initial login) and there on after the server can simply use JWT and no have to lookup the users pw and user in the DB?
I just want to use the JWT to Identity who the user is. I will then authorize then after i have authenticated them. As I know there is a big confused with the new MVC and Authentication and Authorization.
So what my question comes down to.
How can I safely and effectively Implement a Authentication Mechanism Using JWT?
I don't want to just cough something up that seems to work and not have any Idea of the security implications. I am sure that there exists a source some where that has possibly designed a secure mechanism that would suit my requirements.
My requirements are:
Must only have to check db for users credentials once off per session? Due to the use of bcrypt using a lot of resources to compare passwords.
Must be able to identify the user from their request. (I.e who they are, userId will be sufficient) and preferably without accessing the DB as well
Should be as low overhead as possible, with regards to resources on the server side processing the request.
If an intruder had to copy a devices previous request, then he should not be able to access the real users data. (obviously)
Thanks
Your understanding of JWTs is good. But here are a couple corrections and some recommendations.
Authentication and Authorization
JWTs have nothing to do with authentication. Hitting your DB and hashing passwords only happens when you authenticate on creation of the JWT. This is orthogonal to JWTs and you can do that in any way you like. I personally like Membership Reboot, which also has a good example of using JWTs.
Theoretically, you could have the user enter a password once a year and have the JWT be valid that entire year. This most likely not the best solution, if the JWT gets stolen at any point the users resources would be compromised.
Encryption
Tokens can, but don't have to be encrypted. Encrypting your tokens will increase the complexity of your system and amount of computation your server needs to read the JWTs. This might be important if you require that no one is able to read the token when it is at rest.
Tokens are always cryptographically signed by the issuer to ensure their integrity. Meaning they cannot be tampered with by the user or a third party.
Claims
Your JWTs can contain any information you want. The users name, birthdate, email, etc. You do this with claims based authorization. You then just tell your provider to make a JWT with these claims from the Claims Principle. The following code is from that Membership Reboot example and it shows you how this is done.
public override Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
{
var svc = context.OwinContext.Environment.GetUserAccountService<UserAccount>();
UserAccount user;
if (svc.Authenticate("users", context.UserName, context.Password, out user))
{
var claims = user.GetAllClaims();
var id = new System.Security.Claims.ClaimsIdentity(claims, "MembershipReboot");
context.Validated(id);
}
return base.GrantResourceOwnerCredentials(context);
}
This allows you to control with precision whom is accessing your resources, all without hitting your processor intensive authentication service.
Implementation
A very easy way to implement a Token provider is to use Microsoft's OAuth Authorization Server in your WebAPI project. It give you the bare bones of what you need to make a OAuth server for your API.
You could also look into Thinktecture's Identity Server which would give you much easier control over users. For instance, you can easily implement refresh tokens with identity server where the user is authenticated once and then for a certain amount of time (maybe a month) they can continue getting short lived JWTs from the Identity Server. The refresh tokens are good because they can be revoked, whereas JWTs cannot. The downside of this solution is that you need to set up another server or two to host the Identity service.
To deal with your last point, that an intruder should not be able to copy the last request to get access to a resource, you must use SSL at a bare minimum. This will protect the token in transport.
If you are protecting something extremely sensitive, you should keep the token lifetime to a very short window of time. If you are protecting something less sensitive, you could make the lifetime longer. The longer the token if valid, the larger the window of time a attacker will have to impersonate the authenticated user if the user's machine is compromised.
I've written detailed blog post about configuring the OWIN Authorization server to issue signed JSON Web Tokens instead of default token. So the resource servers (Audience) can register with the Authorization server, and then they can use the JWT tokens issued by Token issuer party without the need to unify machineKey values between all parties. You can read the post JSON Web Token in ASP.NET Web API 2 using Owin
For the formal concept . The Authentication is the process of verifying who a user is, while authorization is the process of verifying what they have access to.
Let’s see the real life example
Imagine that your neighbor has asked you to feed his pets while he is away. In this example, you have the authorization to access the kitchen and open the cupboard storing the pet food. However, you can’t go into your neighbor’s bedroom as he did not explicitly permit you to do so. Even though you had the right to enter the house (authentication), your neighbor only allowed you access to certain areas (authorization).
For more detailed and for users who like more STEP BY STEP implementation on practical use of JSON Web Token in WEB API. This is must read post Secure WebAPI Using JSON WEB TOKEN
Updated to use: System.IdentityModel.Tokens.Jwt -Version 5.1.4