Sharing access tokens across instances - oauth-2.0

If I am using client credential grant flow(https://auth0.com/docs/api-auth/tutorials/client-credentials), and I want to renew token on expiry, what is the correct way to use this across multiple instances?
Will multiple instances use different tokens, or a token will be shared and stored in some secure vault for reuse.
What is the recommended approach?

Related

IdentityServer3 organisation for multiple api

I have a DashboardApi and an EnterpriseApi on my system. May be one more later.
I am new at IdentityServer3 and I wonder solve my problem.
IdentityServer saves client applications that will use an api. So I have 2 or 3 api. Will I create IdentityServer for all api? Because DashboardApi will consume EnterpriseApi. EnterpriseApi will consume another api.
And users will login to Dashboard application. I could not imagine the organisation.
To answer the question: you may have one instance of IdentityServer being your identity provider/authority across different "resource" APIs as long as they all point back to that same authority when it comes to token validation.
Then an access token used for "DashboardApi" can be used by "EnterpriseApi". It is important to proxy the token properly and in my experience it would be advantageous to create different scopes for each API to have better access as to which calls may be used to proxy into the second API through the first (especially if user consent is a concern).

How is the correct way to add specific information for Resource Server inside OAuth2 access token?

I have a scenario where my Resource Server (RS) can connect to multiple databases and it can be multi-tenant. It has an environment configuration where I can say: Env A points to database A and belongs to tenant A; Env B points to database B and belongs to tenant B;
Our desktop apps store that information in a data structure that is sent to RS on every call and our web apps store it inside ASP.NET Session. The user select the environment at login.
Now we are moving our APIs completely to REST services and protecting them with oAuth2 using IdentityServer4.
I need to send that environment value to the APIs and I think that should be part of the access token.
The first question is: Is that correct? Can a access token have that kind of information?
The second is: Which is the best IdentityServer4 service that I should extend to inject that value as a claim inside access token and consequently inside ClaimsPrincipal.
The third is: Sometimes I don't have a user to select the environment at login (client credentials grant, for example). In this case, is the correct treat environment as a client claim? There is a way to have dynamic client claims?
Sorry about the long question!
Regards,
Diogo
If that claim is about the users (or clients) identity - yes - it is a candidate for the token.
Add the claim to the resource scopes that represent your API - this way the claim type will be requested in the profile service and you can add it to the token.
Client claims are not dynamic though.

JWT and server side token storage

Every article I've read vouching for the advantages of JWT state that one of these advantages is its ability for an auth system to be distributed across multiple servers. i.e . You aren't relying on a central repository of user auth details to do a lookup on every request.
However when it comes to implementation, I've read in many places that for added security you shouldn't just rely on the JWT signature verification itself, and that you should maintain a list of black or white list tokens generated by the server.
Doesn't this defeat the advantage I've listed above, as this list of tokens would need to be stored centrally where all servers can access it and it would require a lookup on each request?
How have people implemented this on their end?
You are making very good points in your question. Actually it would make sense to store an OAuth token at a central location in order to make it easier to implement signout/revoke functionality. If you just relied on the token signature you couldn't have possibly implemented such feature. Suppose that a user wanted to revoke an access token. In this case if you didn't have a central location/datastore for those tokens where you would have invalidated it and only relied on token signature, then the token would still have been valid.
So indeed, when you want to build more advanced systems that are dependent on OAuth tokens, a central store for those tokens is more than a must.

Access tokens and 2-legged OAuth2

I am learning oAuth2 for the first time. I am going to use it to provide authentication for some simple web services using a two-legged approach.
According to what I have read, the flow should go like this: the web service client supplies some kind of credential to the oAuth server (I'm thinking of using JWT). If the credentials are valid, the oAuth server returns an access token. The web service client then supplies the access token when attempting to use the web service end point.
Here is my question, why not just supply the JWT when making a request to the end point? Why is oAuth's flow conceived this way. Why not just supply to JTW to the end point and use that for authentication? What is the advantage of having the extra step of getting an access token?
Thanks!
You can certainly supply the JWT directly to the web service. The questions is how do you generate it in a way that the service trusts.
A JWT is and access_token, but not all access_tokens are JWTs.
Your client can issue a JWT, sign it with a key (or a cert) and then send it to the API. The advantage of having a 3rd party (an Issuer) is that you can separate authentication from issuing tokens. Clients can authenticate in multiple ways (e.g. usr/pwd, certs, keys, whatever) and then use the JWT to call your API.
The additional abstraction gives you more flexibility and management scalability. For example: if you have 1 consumer of your API, then you are probably ok with a single credential (or JWT, or whatever). If you plan your APIs to be consumed by many clients, then handing that responsibility to a specialized component (e.g. the the issuer) makes more sense.
OAuth BTW, was designed for a specific use case: delegate access to an API to another system on your behalf. You grant access to system-A to access resources on system-B on your behalf with a permission scope.

Is it allowed per the oAuth2 specs to have multiple valid tokens per Resource Owner at the same time?

According to the oAuth2 specs, Is it allowed to have multiple valid tokens per Resource Owner at the same time?
For security considerations it seems appropriate (less exposed area for replay attacks) that only 1 active token per Resource Owner (i.e: User) is available. This would mean that when a new access token is requested for a Resource Owner the existing/old one (if exists) should be revoked.
I can't find any mention of this mechanism. Can someone clarify? Thanks.
I've seen no such restriction in the standard. Having multiple tokens absolutely makes sense and may even improve security for tokens with different scopes. Consider a scenario when the client starts with some basic privileges (e.g. read-only access) and asks for elevated privileges for sensitive operations (e.g. write access). This is very similar to "run as root/admin" in linux/win systems.
Consequently, having multiple tokens with different scopes can make a system more secure if a single token is stolen.

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