IdentityServer4 - How is the API token being validated behind the scenes? - identityserver4

In IdentityServer4 Protecting an API using Client Credentials documentation it is written that:
The job of that middleware is:
validate the incoming token to make sure it is coming from a trusted
issuer
validate that the token is valid to be used with this api (aka
scope)
I have an IdentityServer4 server running on port 5000 and my API is running on port 5001 (2 different servers). I'm wondering what happens behind the scenes in the API when a request comes in with the access token... Does the IdentityServer middleware in the API makes an http call to IdentityServer for each request coming in to the API to validate the token? Does it cahche the token in some way? What actually happen?

Related

Quickbooks Online Integration with Mule

I am trying to integrate Quickbooks online with Mule. So far, I can complete the OAuth dance and retrieve the access token via the HTTP connector using the authorization code configuration.
The steps followed include:
COnfiguring the HTTP Request connector for OAuth dance which includes
Added authorization, callback URL, token URL, and client credentials
Configured payload for saving the access and refresh tokens
To trigger the oauth flow , I hit the authorize URL which in return gives me the realmId and authorization code
To make subsequent requests to the APIs using the extracted token I need the realm ID as well but I am not able to extract that.
The realmId is returned in the initial call along with the authorization code in the payload but when the process happens through mulesoft, there is no way to capture it and without the realmId I cannot make requests to the API.
Following is the XML configuration for HTTP:
<http:request-config name="HTTP_Request_configuration" doc:name="HTTP Request configuration" doc:id="36a1c561-9498-4dbf-b323-5c726b20cb6a" >
<http:request-connection protocol="HTTPS" host="sandbox-quickbooks.api.intuit.com" port="443">
<http:authentication >
<oauth:authorization-code-grant-type externalCallbackUrl="http://localhost:8082/callback" localAuthorizationUrl="https://localhost:8082/login" authorizationUrl="https://appcenter.intuit.com/connect/oauth2" clientId="ABNxxKq4xy1KWs1BteaIIAhY3NC7G5jg9YZg3h15Zf3waDdEja" clientSecret="5k5GxV3HIBtM7DRSQOqlBqtjWfg07tFNAFeW9EeJ" tokenUrl="https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer" localCallbackUrl="http://localhost:8082/callback" state="abc" scopes="com.intuit.quickbooks.accounting">
<oauth:custom-parameter-extractors >
</oauth:custom-parameter-extractors>
</oauth:authorization-code-grant-type>
</http:authentication>
</http:request-connection>
</http:request-config>
I need a way to extract the realmId and set it dynamically instead of hardcoding.
[This is the first request which gets the auth code and realmId before token exchange][2]
This is how realmId will be used in subsequent requests after token exchange
It is to be noted that I am not manually saving and reusing any variables, it is all happening as part of the Mulesoft HTTP connector oauth config
Reference guide for oauth in Mulesoft

IdentityServer4 Multiple API access, single token

We have several API's that we'd like to grant access to a client via client credentials flow. The flow would go something like this.
Client gets a token from is4 based on some scope
Client hits first API with token
Client needs to hit second API with same token.
Authorization of the token at the API endpoint seems to only work when the APIResource matches the APIName in the authentication parameters.
How do you set up APIResource/Scopes such that this scenario can be accommodated?
OK I had the chance to play a bit with your case and have a solution.
So, as you know, the client credentials flow, works based on (except the clientid and client secret) ApiResoirces/Scopes.
Your API's, in their authentication configuration, have:
ApiName - for .NET Core API
RequiredScopes - for .NET Framework API
Depending on your case, you have to set them.
These are the APIResources/Scopes, that your IDS client should have, in its allowed scopes/api resources (Client.AllowedScopes).
Then, when requesting the client credentials, from the token client, you should pass as scope, a string, containing the both scopes/apiresources separated with interval (tokenClient.RequestClientCredentialsAsync("api1 api2");)
Then the access token, that you receive in the response, will be valid for calls for both of your api's.
You also have the second option, in which both your api's use one and the same scope/apiresource, but I don't think that this is a good approach at all.

Do IdentityServer4 API Resources require a secret?

Does not having a secret defined for an IdentityServer4 API Resource introduce a security vulnerability?
I'm a little confused on the Introspection Endpoint, when it is used, and whether or not someone could use the Introspection endpoint to bypass Authorization and access an API without a defined secret (by a POST with just the API name as a parameter).
Is this possible? Or is the introspection endpoint only authorized through defined clients that use something like the Client Credential Grant?
The introspection endpoint will only validate a posted token, it shouldn't accept an API name in its request.
It can be used to validate reference tokens (or JWTs if the consumer does not have support for appropriate JWT or cryptographic libraries). The introspection endpoint requires authentication using a scope secret.
http://docs.identityserver.io/en/release/endpoints/introspection.html
This shouldn't be an endpoint you need to implement, it is included by identity server in the same way as the '.well-known/openid-configuration'.
A use case for this endpoint would be an API being passed a token and wanting to confirm its genuine and still valid (not expired or revoked), the response would include the claims associated with the token (users claims with the tokens scope taken into consideration)
For introspection security considerations see the RFC 7662 Section 4
An API Resource requires a Client Secret when you are using the Authorization Code Flow as its sending claims on the back channel.
If you are using Reference tokens you will also require a Client Secret, as the access token is never presented to the client, but instead the reference token is passed from the client to the api resource, and then onto the identity server in exchange for the access token.
It really depends on the client and the flow.

How to interact with back-end after successful auth with OAuth on front-end?

I want to build small application. There will be some users. I don't want to make my own user system. I want to integrate my application with oauth/oauth2.0.
There is no problem in integration of my front-end application and oauth 2.0. There are so many helpful articles, how to do this, even on stackoverflow.com. For example this post is very helpful.
But. What should I do after successful authorization on front-end? Of course, I can just have flag on client, which says "okay, mate, user is authenticated", but how I should interact with my backend now? I can not just make some requests. Back-end - some application, which provides API functions. EVERYONE can access this api.
So, I need some auth system anyway between my FE and BE. How this system should work?
ps I have some problems with English and may be I can not just correctly 'ask google' about it. Can you provide correct question, please :) or at least give some articles about my question.
UPD
I am looking for concept. I don't want to find some solution for my current problem. I don't think it is matters which FE and BE I use (anyway I will
provide information about it below)
FE and BE will use JSON for communication. FE will make requests, BE will send JSON responses. My application will have this structure (probably):
Frontend - probably AngularJS
Backend - probably Laravel (laravel will implement logic, also there is database in structure)
Maybe "service provider" like google.com, vk.com, twitter.com etc remembers state of user? And after successful auth on FE, I can just ask about user state from BE?
We have 3 main security concerns when creating an API.
Authentication: An identify provider like Google is only a partial solution. Because you don't want to prompt the user to login / confirm their identity for each API request, you must implement authentication for subsequent requests yourself. You must store, accessible to backend:
A user's ID. (taken from the identity provider, for example: email)
A user token. (A temporary token that you generate, and can verify from the API code)
Authorization: Your backend must implement rules based on the user ID (that's your own business).
Transport security: HTTPS and expiring cookies are secure and not replayable by others. (HTTPS is encrypting traffic, so defeats man-in-the-middle attacks, and expiring cookies defeats replay attacks later in time)
So your API / backend has a lookup table of emails to random strings. Now, you don't have to expose the user's ID. The token is meaningless and temporary.
Here's how the flow works, in this system:
User-Agent IdentityProvider (Google/Twitter) Front-End Back-End
|-----------------"https://your.app.com"---------->|
|---cookies-->|
your backend knows the user or not.
if backend recognizes cookie,
user is authenticated and can use your API
ELSE:
if the user is unknown:
|<--"unknown"-|
|<----"your/login.js"----------+
"Do you Authorize this app?"
|<------------------+
|--------"yes"----->|
+----------auth token--------->|
|<---------/your/moreinfo.js---|
|-------access_token ---------->|
1. verify access token
2. save new user info, or update existing user
3. generate expiring, random string as your own API token
+----------->|
|<-------------- set cookie: your API token --------------------|
NOW, the user can directly use your API:
|--------------- some API request, with cookie ---------------->|
|<-------------- some reply, depends on your logic, rules ------|
EDIT
Based on discussion - adding that the backend can authenticate a user by verifying the access token with the identity provider:
For example, Google exposes this endpoint to check a token XYZ123:
https://www.googleapis.com/oauth2/v3/tokeninfo?id_token=XYZ123
I read through all the answers very carefully, and more than half the people who responded are missing the question completely. OP is asking for the INITIAL connection between FE & BE, after the OAuth token has been issued by the Service Provider.
How does your backend know that the OAuth token is valid? Well keep in mind that your BE can send a request to the Service Provider & confirm the validity of the OAuth token, which was first received by your FE. This OAuth key can be decrypted by the Service Provider only because only they have the secret key. Once they decrypt the key, they usually will respond with information such as username, email and such.
In summary:
Your FE receives OAuth token from Service Provider after user gives authorization. FE passes OAuth token to BE. BE sends OAuth token to Service Provider to validate the OAuth token. Service Provider responds to BE with username/email information. You can then use the username/email to create an account.
Then after your BE creates the account, your BE should generate its own implementation of an OAuth token. Then you send your FE this OAuth token, and on every request, your FE would send this token in the header to your BE. Since only your BE has the secret key to validate this token, your application will be very safe. You could even refresh your BE's OAuth token on every request, giving your FE a new key each time. In case someone steals the OAuth token from your FE, that token would be quickly invalidated, since your BE would have already created a new OAuth token for your FE.
There's more info on how your BE can validate the OAuth token. How to validate an OAuth 2.0 access token for a resource server?
let's use OAuth concept to begin,FE here is Client , BE here is Resource Server.
Since your client already authorized, Authorization server should grant
Access token to the client.
Client make request to the resource server with the Access token
Resource server validate the Access token, if valid, handle the request.
You may ask, what is the Access token, Access token was issued by authorization server, grant to client, and recognized by resource server.
Access token is a string indicate the authorization information(e.g. user info, permission scope, expires time...).
Access token may encrypted for security, and you should make sure resource server can decrypt it.
for more details, please read OAuth2.0 specification https://www.rfc-editor.org/rfc/rfc6749.
Well you don'y need User-System on your Front End side.
The front end is just a way to interact with your server and ask for token by valid user and password.
Your server supposed to manage users and the permissions.
User login scenario
User asking for token by entering his username and password.
The server-API accept the request because it's anonymous method (everyone can call this method without care if he's logged in or not.
The server check the DB (Or some storage) and compare the user details to the details he has.
In case that the details matches, the server will return token to the user.
From now, the user should set this token with any request so the server will recognize the user.
The token actually hold the user roles, timestamp, etc...
When the user request for data by API, it fetch the user token from the header, and check if the user is allowed to access that method.
That's how it works in generally.
I based on .NET in my answer. But the most of the BE libaries works like that.
As am doing a project for SSO and based on my understanding to your question, I can suggest that you create an end-point in your back-end to generate sessions, once the client -frontend- has successfully been authorized by the account owner, and got the user information from the provider, you post that information to the back-end endpoint, the back-end endpoint generates a session and stores that information, and send back the session ID -frequently named jSessionId- with a cookie back to the client -frontend- so the browser can save it for you and every request after that to the back-end considered an authenticated user.
to logout, simply create another endpoint in the back-end to accepts a session ID so the back-end can remove it.
I hope this be helpful for you.
You need to store the token in the state of your app and then pass it to the backend with each request. Passing to backend can be done in headers, cookies or as params - depends on how backend is implemented.
Follow the code to see a good example of all the pieces in action (not my code)
This example sets the Authorization: Bearer TOKEN header
https://github.com/cornflourblue/angular-registration-login-example

how to authenticate/authorize fetchr requests

How can I expose the req.session server side to the fetchr service requests so that I can authorize the requests? Can I have access the the session or the request object somehow from the crud methods?
An alternative to session would be to set a bearer token on the client side and pass that in as well. However, this would make it difficult for isomorphic rendering as we wouldn't have access to that token server side.
Are there any simple fluxible fetchr examples requiring authenticated services, e.g. read myAccount?

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