I'm trying to setup an application to validate identity using Azure AD and acquire a token to allow access to a secure api. The front end application is written in angular and allows anonymous access. What can I use to access AAD authenticate and return an access token?
This will be an angular 6+ UI that is communicating to a secure .Net api using Azure AD for authentication. I have done a couple days research and everything points to a user logging in to authenticate using the login page. I need it to be by app and open the login page. I tried a couple examples where it utilized authentication/authorization and that didn't work because the app needs to authorization the user to talk to the api. I have seen where people were using Microsoft graph but once again it was user based and they were redirected to an azure login. I am looking for a solution that will allow me to setup an account in azure ad and authenticate the app on start to get an access token to allow communication to my secure api. If I have missed something somewhere in my research and test attempts let me know. This is my first Azure AD auth attempt and I feel like I am missing something for application authorization.
The problem is an Angular app is what we call a public client.
It cannot hold secrets and thus cannot prove its identity.
So, only user-based authentication flows should be used by public clients.
Confidential clients on the other hand can hold secrets as they run on servers that you control.
So for example, a back-end Web application or API would be a confidential client.
Those can use the client credentials flow to acquire access tokens and call APIs as themselves without a user being involved.
There is a bit of a fundamental issue in your question.
Your API requires authentication, but you want functionality to be available to anonymous users.
So you want to bypass authentication.
If you really want to bypass authentication for parts of the API, you could just make those endpoints available anonymously without a token.
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I have to design an IAM solution for a NodeJS microservice using Auth0. Objective is to allow third party mobile application users to access this microservice.
I understand OAuth and OpenID connect solution and one simple solution is third party application accesses APIs as a client using client credentials workflow.
Solution I have to design is allowing users to login and authenticate using their Enterprise IdP connected to our Auth0 Server. So that we can implement authorization and access control at user level.
At the same time customer application needs to be kept agnostic of Auth0 service.
What I mean by it is client should not be required to add any logic in their application for accommodating our Auth0 domain like we have in first party React application. user once logged in to customer application should get access to our API also by using SSO capability. I have read some documents about configuring customer IdP with our Auth0 server acting as a SAML SP. Still I could not understand hows of it and will Auth0 create an OAuth access token in this scenario.
I realise this requires an app to intermediate between customer's mobile app and our API service. Still, I am not able to understand data flow and communication between various components.
Also, I am not sure it is a common situation or requirement? If it is is there any technical term for it? This not seem like a standard B2B scenario.
have to design an IAM solution .. , I am not able to understand data flow and communication between various components ..
Before answering, the answer will points the asked specific questions, may not fit al your needs. SO is not really intended for writing tutorials or searching the documentation. Implementing an IdP (effecively a security module), one needs to do his homework and learn the details.
Maybe using an ready / out of box solution could be interesting. Using an open source IAM such as KeyCloak, WSO2IS could be a quick start. Or cloud services such as AWS Cognito, IBM AppId, Azure AD, .. could be a feasible solution too
a client using client credentials workflow .. access toked received by our API should be for user logged in
The client credentials grant is intended to authenticate only applications. That's it.
To authenticate users, other grant type is needed. For the user authentication the most common option is the authorization code or the implicit grant. The implicit grant is has its weaknesses and is being replaced by the code grant with PKCE (just search it).
End requirement is users of 3rd-party application not required to login again while 3rd-party application fetches data from our API .. Configuring their IdP (most probably Active directory) and our Auth0 servers for the same is all I need to understand
I see most common two options in use:
1. federated SSO authentication
This is the most commonly used option. The external (3rd party) IdP is configured as a "trusted" federated IdP. You often see the scenario when you have a service provider allowing to login with other IdP, often social networks (FB, Google, ...)
The login flow is as follows:
The client authorizes with the provider's (yours) IdP (let's call it IdP1).
IdP1 now acts as as Service Provider with IdP2 (IdP of the partner) and asks for the authorization (redirects the user to the IdP2).
User is authenticated and authorized with IdP2. If the user is already authenticated, the IdP2 doesn't need to ask the user's credentials again, this is how SSO works on this level
IdP2 returns to IdP1 (acting as a service provider).
IdP1 reads the user information (using the id_token, userinfo service - assuming using the OAuth2/OIDC protocol all the time there are other protocols too) and builds its own the user-level token. It may or may not create a local user (it is called user provisioning).
IdP1 returns to the client and the client can request a user-level token.
Then the client can call the API services with the token trusted by the API provider.
2. Assertion Framework for OAuth Authorization Grants
This option is built on top of the Assertion Framework for OAuth 2.0 Client Authentication and Authorization Grants, it is an optional extension of the OAuth2 protocol. I call this a token swap service
Basically the token service could validate the access or ID token of a trusted (partner) IdP and issue its own token based on the provided user information.
As you see there are a lot of information and to build a secure solution you ned to make sure that all steps are properly secured (signature, expiration, issuer, validity, audience, subject domain, .. are validated). Disclaimer - as my job we implement IAM/IDM solutions and a lot can get wrong if shortcuts are taken. So you may really consider using an out of box and proven solution.
Be warned possibly noob question ahead.
I'm a little unsure where exactly Azure AD or IdentityServer is supposed to fit in in the overall communication flow.
Here is a scenario that I often face.
Some "dumb" client (e.g. a Windows App that can't use external assemblies or some JavaScript in a web app) has to contact my Web API which will then contact other APIs or other resources.
If I want to try and implement either Azure AD or IdentityServer as a means of authentication and authorization in the Web API, I don't see that this can be done in any other way, than it has to be the Web API that communicates with Azure AD or IdentityServer as the client doesn't have the ability to do so due to the lack of required assemblies.
If this assumption is not correct, then how would I do this?
If it is correct however, then what means of security is there between the client and the Web API other than communicating over HTTPS when the client has to send it's credentials to the Web API, so the Web API can authenticate and authorize the user against either Azure AD or IdentityServer?
If I understand your requirements correctly, then you are able to change the client Windows app, but unable to add external assemblies to it? So you would not be able to add the ADAL NuGet package to it.
You can still use Azure AD authentication - it is possible, but not trivial, to implement the client code yourself.
Or you can, as you already mentioned, pass the user's credentials to the Web API somehow, and then use that to have the Web API do authentication towards Azure AD on behalf of the user. There is a sample app which shows how to use username/password credentials.
This however, goes against the whole OAuth/OpenIdConnect mindset, where your app should never know the user's credentials.
Here:
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/active-directory/develop/active-directory-v2-protocols-oidc.md
Be careful with trying to use the most recent version of the Azure AD endpoint (just don't use version 2.0, they shot themselves in the foot by excluding all Azure AD webapp registrations & by "securing" web APIs by making them only available to apps with the same appid - as far as I'm concerned, it's unusable until they fix those two issues) - see the "[!NOTE]" near the top of that linked page for the v2.0 limitations.
I am currently being tasked with writing an RESTful API that we are going to release to our clients. I plan to use Web API 2 with OWIN middleware. The applications that will be accessing this can range anywhere from a Console app with no additional user authentication to full blow web applications that will involve user login and authentication.
One other requirement is that we need not only provide user authentication to control what data we will return, we also need to authenticate that the application accessing our API is allowed by our organization. So this requires us to not only validate the application invoking our API's but also the many users logging in via that application.
The goal is to use a bearer token technology like OAuth 2. I am not very familiar with OAuth 2 but after looking it over I don't see a way to facilitate a two part authentication like this. Ideally we would like to issue a clientId and a clientPassword and they would pass this in along with the userid and userpassword and we would then pass a token back.
Is this something that anyone has tackled before using OAuth2 or is this a job for a custom auth solution?
What you describe sounds like fairly standard Oauth2.0 scenarios so you shouldn't need anything custom.
For the web apps you could use the Resource Owners Password Credentials Grant. Which is a standard flow.
This allows your Oauth client to pass in its client Id and client secret along with a user's Id and password to your Auth Server which can then validate both the user and the client before issuing a token in response.
But I would recommend using the Authorization Code Grant which is probably the best option for web applications and it involves both the client and the user being effectively authenticated.
For you console apps, or any apps which are not user specific, you can use the Client Credentials Grant. This allows the app to authenticate and to get a token without a user.
If you need your API to be aware of the client application, the only flow you can't really use is the Implicit Grant which doesn't authenticate the client.
I have followed the great example on integrating ADAL and Xamarin Forms by Vittorio. I am still struggling though on how to best implement authentication in mobile applications based on Xamarin Forms.
What is the best way to authenticate a user in a mobile application base on Xamarin (forma) knowing that the user is registered in an Active Directory on premise which is synced to an Azure Active Directory? Currently I am using ADAL for that but would it perhaps be better to use Azure Mobile Services? I need a token so that I can authenticate a user in a webapi running in Azure Websites.
When I follow the example of Vittorio, I run into a problem that I don't get a refresh token from the AAD authentication call. I should not that my AAD redirects the real authentication call to an on premise ADFS server. I am not sure if that could be the problem?
for #1 you can use the ADAL sample exactly as is - the only difference is that you need to configure your app to request access to your web API and pass the API resource is when you acquire a token. See setup instructions in https://github.com/AzureADSamples/NativeClient-DotNet.
For the refresh token: ADAL used it automatically from its cache, but people often did not know/understand that and used the returned refresh token manually, doing a lot of extra work... So we are no longer returning the token in the result, but we do use it automatically whenever you call acquiretoken and the token needs renewing.
I am currently developing a web application that is right now comprised of a front end which displays and interacts with the data using a REST API we have written. The only thing that will ever use the API is our front end website, and at some point a mobile app that we will develop.
I have done a lot of reading about how OAuth is the ideal mechanism for securing an API and at this point I am starting to have a good understanding of how it works.
My question is -- since I am never granting access to my API to a third-party client, is OAuth really necessary? Is there any reason it is advantageous? Furthermore, because the back end is simply the API, there is no gateway for a user to authenticate from (like if you were writing an app using the Twitter API, when a user authenticates they would be directed to the Twitter page to grant to access then redirected back to the client).
I am not really sure which direction to go in. It seems like there must be some approach halfway between http authentication and OAuth that would be appropriate for this situation but I'm just not getting it.
From my point of view, one of the scenarios that favor OAuth over other options is to work with untrusted clients, no matter if these are developed by you or a third party.
What's an untrusted client? Think from the point of who handles the credentials that grant access to your API.
For example, your web application could interact with your API in two falvors:
Your web app server side talks to your API. Your web app server is a trusted client because the credentials to access your API can only be access by whom have access to the server...You and your team. You could authenticate your web app server with a client_id and a client_secret.
You may want to make calls directly to your API from your Web app client, which runs on the end user's browser using JavaScript. The end user's browser is an untrusted client. If you were to deliver the credentials to your API down to the browser, anyone could check the JavaScript code and steal your credentials.
A third party Native App is also untrusted. A malicious developer that uses your API could save the credentials of and end user of your platform.
Your Native App is a trusted client and could manage the authentication with a simple username , password and a client id identifying your App.
How can OAuth help? OAuth Authorization code and Implicit grants can help you with this issue. These flows only work with clients that support a redirect, like a browser. And let you authenticate an untrusted client and a user against your Authorization Server to gain access to your Resource Server, your API, without exposing the credentials. Take a look at the RFC to see how it is done.
The good thing of OAuth is that it not only supports these redirect based authentication flows, but it also supports client credentials grant and user credentials grant. So an OAuth Authorization Server would cover all cases.
OAuth 2.0 originally seems like a PITA if you think about having to build a lot of it yourself, but most languages have some really solid OAuth 2.0 setups which you can just bolt in with varying amounts of fiddling. If you're using a framework like Laravel or RoR then it's barely any work.
PHP: http://oauth2.thephpleague.com/
Ruby (Rails or Grape): https://github.com/doorkeeper-gem/doorkeeper
If you don't want to redirect users as suggested in your post then ignore other comments and answers that talk about two legged flows. You can use the client_credentials grant type to have apps just provide their client id and secret in return for an access token, which is nice and easy.
I would ask how private are we talking, because if the only systems talking to it are within the backend and have no interaction with the outside world you could probably leave it wide open and just rely on the network to keep it safe (VPN/Firewall).
But if it's private in the sense of "our iPhone app uses it" then you definitely want to go with OAuth 2.0, or something like it.
2 legged OAuth is probably what you want to use. It's basically hashing a shared key, but you have the advantage of not having to write the code yourself.
Here's a related question: Two-legged OAuth - looking for information
You should use Oauth for mobile device to API layer communication.
However, there is no benefit of Oauth in this web UI layer to middle-layer access (machine to machine).
On the other hand there are some potential issues
Managing the access token expiry becomes a pain. Consider that your UI has to cache the access token across multiple nodes in a cluster. Refresh it when expired, and the fact that UI layer is negotiating security with backend will just take extra time once in a while.
In two legged Oauth (OAuth Client Credential as in v2.0) does not support any encryption. So you still need to send key and secret both to the server for getting an access token.
Backend has to implement issuing access token, refresh token, validating access token etc, without any significant benefit