Azure AD Securing API - GetAccessTokenForUserAsync not include claims roles - .net-core

I have a web site that calls an API. To call the API from the web site I'm getting first a jwt token using GetAccessTokenForUserAsync(scope).
My problem is that this method doesn't retrieve user's roles inside the jwt token.
My user.identity.claims has a few roles but they are not include in the jwt token.
What I'm missing?
I'm to trying to including the roles in the jwt token because I need to secure my api methods. For example, a method can be called only by AdminMember, other method only can be called by SpecialMember.
Is there another way to secure my api without sending my user's roles?
Thanks

Since the roles are defined in your client app's registration, they will only be available in its tokens.
So, there are fundamentally two options:
Define the same roles in the API app registration as well. You will need to assign the roles on that app as well to the users. This could be made easier by using groups for the role assignments.
Change the API to use the same app registration. Now you will get the roles in the access token. Using one app registration can mean violating least privilege since then any permission you want to give to either the API or client app will be given to the other as well.
Depending on your case, you can choose either option :)

Related

Mixed Authentication in .net core API

I'm building a multi tenant Service Fabric Application, that allows a tenant to specify a login type - Identity(asp.net)/Azure AD.
I have an Authentication service that checks to which tenant the user is linked to and then proceeds to check if the username:password for the user is valid, if valid it returns a JWT token to the gateway API/web API that then allows access to the rest of the services on the cluster.
This is further secured by roles to limit actions and data access etc.
Question 1
What would be a secure way to save the app id and secret given by that tenant if they use azure AD?
In my DB and encrypt the info, it would have to be decrypted to connect to the AD(Trying to keep in dynamic).
Question 2
I'm implementing my own sliding refresh tokens to obtain a new JWT after it expires, is there a better/standard approach?
Question 3
Is there a better/standard way to handle this multi-tenant sign in process.
Question 4
Is there a way to have optional claims set on the JWT Subject that would allow access to shared services but prevent access to tenant specific services if the claim value is incorrect?
Edit
Ideally the Roles should not be part of the tenants AD/B2C because they role are dynamic and managed from within the application.
Instead of building your own STS logic, have a look at IdentityServer, a popular and great OSS tool.
For example, have a look here for a multi-tenant example using asp.net core.
It supports adding custom claims to the token, by implementing a Profile Service. Services can be configured to use claims for authorization.
This blog post may also be useful.
I will very strongly advise you ride upon the Azure tenant model and let Azure AD manage all credentials and authentication. In today's world its a very bad idea to store and manage user credentials when there are plenty of Identity Providers available.
Recommended reading:
How to build a multi-tenant app with Azure AD
How to secure a Web API with Azure AD.
Libraries like MSAL.NET will automatically manage token caches and refreshes.
Use roles and groups in Azure AD
Claims in tokens issued can be customized to some extent.
disclaimer: I work for Microsoft

What is the purpose of using two tokens in firebase ? - firebase authentication query for a server client web application

Firebase provides a client sdk for web and an admin sdk for backend server to create a user session. In a microservices architecture based cloud application, do we have to create a custom token at the server side when a user tries to log into our system and then allow the client using java-script based client sdk to create another id-token with the custom token for continuing the client interaction within that session ?
Why do we need two tokens i.e Custom Token(Admin SDK) and Id Token(Client SDK) for user authentication ?
You need only one of the two tokens for each user, depending on whether you're using a custom provider to sign that user in, or one of the built-in providers.
If you use one of the existing providers you'll use its ID token.
If you create a custom provider, you'll create your own (custom) token for the user. This custom token essentially takes the place of the ID token that you'd use with the default provider.
To learn all about the various token types that Firebase Authentication has, read the blog post Demystifying Firebase Auth Tokens.

How to get access token from Single Sign On portal for multiple sites

We are building several websites/products, if a user has an account on one site they will also be allowed access to all other sites.
Let's say we have the following setup:
Clients
site1.com
site2.com
Single Sign On Portal
sso.company.com
APIs
api1.company.com
api2.company.com
The Single Sign On Portal supports multiple OAuth providers, such as Google, Microsoft, Facebook, etc and this is all working great built on top of the default ASP.NET Web Forms template in VS 2015 using OWIN and Idenity.
The SSO site is logging the user in an using a cookie for authentication, which works fine while still on the SSO site. Now we need to return a token that the client site can use to know that the user is authenticated
Now the challange here is how do we exchange the cookie to a token that we can return to the client(s) to use in the Authorization header in request sent to our APIs?
Should we generate a token our selves or is there some built in functionality we can use for this purpose?
I've seen most people generate a token themselves and then multiple accounts can be linked to that same user in your account (i.e. a user could log into both FB and Google). Most of the SSO providers have a way to get an identity token or one time use code for your server to use and get user info like FacebookId. The key is ensuring that identity token came from FB and not a third party.
Auth0 is a pretty good service if you want a managed route. Even if you don't use them, they have a lot of good resources on oauth. (I have no affiliation with them other than that we used them before.) we also have a little more info on auth: https://www.moesif.com/blog/technical/restful-apis/Authorization-on-RESTful-APIs/

Is it possible to use an external Identity Provider in a Web API with ASP.NET 5?

Reading this question, #Pinpoint's answer and the further discussion on comments, I'm well aware that natively we can't add an identity provider to our apps developed with ASP.NET 5. One possible replacement for the legacy OAuthAuthorizationServerMiddleware is then provided by the AspNet.Security.OpenIdConnect.Server as I've found in many places.
Now, there is one point that I'm still unsure about all this because I'm really not an expert in security, so my knowledge about OAuth is not very deep. My doubt is the following: is it possible to use an external identity provider when using OAuth to protect one RESTful API?
Notice that I'm not talking about adding social login to one website, I'm talking about using one external identity provider in one RESTful API.
My point is, this makes me a little confused yet, because I always thought this should be a concern of my app.
So my question here is: when using OAuth and ASP.NET 5, is it possible to use an external identity provider, other than implementing one? If it is possible, how this works in short? I mean, my app still needs to be able to manage the identities of users, in the sense that it needs to manage claims and so on.
In that case, if it is really possible, how the flow would be? The external identity provider should issue the tokens? But how my app would be able to verify those tokens and manage users identities?
EDIT: One of the reasons I feel unsure about that is that when we use the UseOAuthAuthentication extension method, we set up one callback path which is described as
The request path within the application's base path where the user-agent will be returned. The middleware will process this request when it arrives.
Now, if we are developing a site, then this really does make sense. The person goes there, click a button to login with a provider like Facebook. The user is redirected to Facebook's page and then after he logs in, he is redirected to some page of the site.
On the other hand, with a RESTful API this is meaningless. There is no notion of being redirected.
This makes it seems that the usage of external providers is only for sites and not for RESTful API's. This is the main point of my question.
My doubt is the following: is it possible to use an external identity provider when using OAuth to protect one RESTful API?
Yes, it's definitely possible. This is exactly what you do when you use Azure Active Directory to protect your API endpoints:
app.UseOAuthBearerAuthentication(options => {
options.AutomaticAuthenticate = true;
options.Authority = "https://login.windows.net/tushartest.onmicrosoft.com";
options.Audience = "https://TusharTest.onmicrosoft.com/TodoListService-ManualJwt";
});
The next legitimate question is: if you can use the tokens issued by AAD to protect your API, why couldn't you do the same thing with Facebook or Google tokens?
Unlike Facebook or Google, AAD issues completely standardized tokens named JWT tokens that the OAuth2 bearer middleware can "read" and "verify" to determine whether the token is still valid and was really issued for your API (i.e if the audience attached with the token corresponds to your API. You can control this value using the resource parameter when making your authorization request).
You can't do something similar with FB or Google tokens, since they are totally opaque. Actually, it's not really surprising since these tokens have only one objective: allowing you to query FB or Google APIs, not your own ones (these social providers don't allow to set the audience of the access token).
Since you can't read the token yourself, the only option is to ask FB or Google whether it is still valid to make sure your API doesn't accept invalid tokens. That's something you can (easily) do with Facebook as they offer a "token inspection endpoint" you can query for that: https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow (see the Inspecting access tokens chapter). This way, you can ensure the token is not expired and determine the user corresponding to the token.
Sadly, this approach has two downsides:
You have to make an extra HTTP call to the Facebook endpoint to validate the access token, which implies caching received tokens to avoid flooding Facebook with too many requests.
As the access token is not issued for your own API, you MUST absolutely ensure that the access token was issued to a client application you fully trust, or it will allow any third party developer to use his own FB/Google tokens with your API without having to request user's consent. This is - obviously - a major security concern.
You can find more information in the last part of this SO answer (it's for Katana and about Dropbox, but you should get the idea): OWIN/OAuth2 3rd party login: Authentication from Client App, Authorization from Web API
So my question here is: when using OAuth and ASP.NET 5, is it possible to use an external identity provider, other than implementing one? If it is possible, how this works in short? I mean, my app still needs to be able to manage the identities of users, in the sense that it needs to manage claims and so on.
In that case, if it is really possible, how the flow would be? The external identity provider should issue the tokens? But how my app would be able to verify those tokens and manage users identities?
To work around the limitations mentioned in the previous part, the best option is - as you've already figured out - to create your own authorization/authentication server. This way, your API doesn't (directly) accept FB or Google tokens but the tokens issued by your own server, that can possibly redirect your users to FB or Google for authentication.
This is exactly what this sample does: https://github.com/aspnet-contrib/AspNet.Security.OpenIdConnect.Server/tree/vNext/samples/Mvc
The user is invited by the client application (Mvc.Client) to authenticate with your authorization server (Mvc.Server) so he can get an access token to later query the API (also in Mvc.Server). For that, the user is redirected to your authorization server, which itself offers you to authenticate with Google or Twitter.
When this external authentication step is done, the user is redirected back to your authorization server (Mvc.Server), where he's asked to give his consent for the client app (Mvc.Client) to access his personal data.
When the consent is given, the user is redirected back to the client application with the access token you can use to query the API endpoint.

ADFS in ASP.NET usage

I am relatively new to uisng ADFS (in ASP.NET) which is what my company wants to use and just have a few basic questions about that:
Am I correct there is no explicit "Authorize" call you can do like with ASP.NET Membership Providers? Unless you on a domain it presents you with a login screen and once you enter credentials it does validation and returns back a token with claims information.
Can you configure some forms to allow anonymous access like you can do with Forms Authentication?
Thanks.
Yes, you can setup pages in your app that don't require authentication. It works exactly like you'd do with Forms Auth.
On #1: in a claims based model, your app relies on an external system to authenticate users and receives evidence that the user is valid in the form of a token. You can completely automate this (using WIF and config files), or you can explicitly trigger the authentication process. In any case, your app won't be responsible for validating legitimate users anymore. It is a responsibility that it delegates to the STS (e.g. ADFS). That's why apps are called "relying parties".
I'd suggest you read the first couple chapters of the A Guide to Claims based Identity for a better understanding of the underlying principles.

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