Azure Application Proxy Does Not Accept Authorization Header - azure

I have been trying to configure access to an on-premise Web API from a native application using this walkthrough: How to enable native client applications to interact with proxy applications
According to the walkthrough,
"To support native client applications, Application Proxy accepts Azure AD-issued tokens that are sent in the header."
However, regardless of the tokens that I send in the request header, the proxy always responds with HTTP 302 and redirects me to the sign in page.
Has anyone been able to pass Azure app proxy pre-authentication using a token?

Related

how to obtain JWT token in a api gateway architecture

Currently doing some research to setup an (azure) api gateway with oauth (jwt token) security.
an external partner/app sends a request to an api endpoint published on the gateway including a valid JWT-token in the header that gets validated by the gateway against AzureAD for example. When validated the request is routed to the backend service. No problems here.
My question is, what is best practice for the external app to obtain that JWT-token (to use for the api call) ?
Obviously, It could send a request to AzureAD with a clientid+secret to obtain a valid JWT token. But to do so it has to call my internal AzureAD directly ? Is this the way to do it ?
or should I expose a 'get-jwt-token' api on my api gateway and route that request to AD ? How should I secure that API ? with basic auth ?
or am I missing something, and is there a much better best/proven practice ?
HOSTING BEST PRACTICE
A reverse proxy or API gateway is placed in front of both APIs and the Authorization Server (AS). This ensures that an attacker who somehow gains access to the back end entry point cannot access data sources.
OAUTH REQUESTS TO GET TOKENS
OAuth requests are typically proxied straight through the reverse proxy / API gateway to the AS with no extra logic. All credentials, auditing of login attempts etc remain in the AS.
MANAGED SERVICES
If using Azure AD as a cloud managed AS, this is a special case: the system is already hardened for internet clients, so most companies don't add their own proxying - though it is possible to do so.
FURTHER INFO
The first of these covers the infra setup and the second gives you an idea of extensibility options once a reverse proxy / gateway is in place.
IAM Primer
API Gateway Guides

Calling on-premise OAuth API through Azure Application Proxy

I have a on-premise API that use OAuth, so I use the "Authorization:Bearer ..." header when calling it from on-prem. Now I want to call this API from external using Azure Application Proxy with authentication. I know how to acquire a Bearer Token to authenticate against the Application Proxy.
The problem is that in the same HTTP Call to the on-prem API from external, I need to have 2 different "Authorization:Bearer ..." headers, one for the Application Proxy and one for the on-prem API.
I cannot just have 2 Authorization headers, right? So how do I call my on-prem API from external?
Edit : I've never found the real solution so I built an "On-Premise Proxy" that swap Authorization:Bearer after the Azure App Proxy. Here's how it works :
The outside app inserts 2 headers with the call to Azure App Proxy (AAP). First is Authorization:Bearer with the token required by AAP. The second is a dummy header "AuthorizationOnPrem" with the token that is required by the app behind the Azure Proxy (on-prem).
The Azure Proxy redirect the call to my custom "On-Premise Proxy".
This On-Prem Proxy copy the token from AuthorizationOnPrem to Authorization.
Then the On-Prem Proxy call the real on-prem app with the same data that it got called but with the right token.
I know it's quite patched but it worked for me with the on-prem app I needed. And it was surprisingly easy to do. Might not scale well though.

How to access web-app through an Azure Application proxy with an access token

I have a web app configured in my Azure AD.
On a machine, i have installed a connector and configured an application proxy with that connector.
I am now trying to connect from an Android mobile application to the web app through the application proxy.
If I use a WebView inside my app, I can load the User access URL, enter my credentials and I receive a cookie for use by following connections.
I need to be able to use other HTTP clients that do not have the possibility to show UI.
I was wondering if it was possible to somehow request access and refresh tokens, and add those to future requests. or if possible convert them to a cookie in some manner and add that in a header.
Your client app can simply use MSAL (or ADAL, or another OpenID Connect client library) to sign the user in and an access token for the App Proxy app. Then you can include that token in the Authorization header in requests to the endpoint from App Proxy. App Proxy will recognize it, validate it, and (if everything checks out) proxy the call down to the App Proxy connector, where the rest of the process happens as normal.
Here are the relevant docs: https://learn.microsoft.com/en-us/azure/active-directory/manage-apps/application-proxy-configure-native-client-application

Turning on Azure Mobile Service Authentication results in "Resource does not support GET" on a POST Request

I tried to implement custom Authentication via a authentication endpoint in an azure mobile app. I've created an Api Controller, that creates the Jwt using Azures AppServiceLoginHandler.CreateToken method. When I post to this controller with turned off Azure App Service Authentication, I get a token, but when I want to use it later, I always receive a "401 Unauthorized".
But when I turn the setting on in the Azure Portal, and send the very same request
I get:
The requested resource does not support http method 'GET'.
I'm not changing any code, and I'm certainly using a POST request - The exact same request, that works with turned off App Service Authentication.
My Code is essentially the same as here:
https://www.newventuresoftware.com/blog/custom-authentication-with-azure-mobile-apps
Could someone enlighten me here? Do I need additional configuration somewhere?
As adrian hall's book about Custom Authentication states as follows:
You must turn on Authentication / Authorization in your App Service. Set the Action to take when request is not authenticated to Allow Request (no action) and do not configure any of the supported authentication providers.
For custom authentication, you need to turn on the Authentication / Authorization in your app service for authenticating your token. Moreover, I would recommend you leverage fiddler to capture the network traces to narrow this issue. Additionally, you need to make sure that you send the custom login request with HTTPS. Details, you could follow this similar issue.

Authorising a .net user-application through Google or Twitter

My question is [Similar to this one1, but with third party providers instead of active directory.
I have an end-user UWP app, and I want to consume my Azure API App. I am NOT Azure mobile app and it's client side SDK.
Most of documentation is of sort "copy paste this magic code" and never explains how authentication actually happens.
I was inspecting mobile app SDK because Microsoft's documentation says that it's auth. process is the same.
From what I see, the mobile App SDK opens a web-view very similar to that produced by a WebAuthenticationBroker. Then every request to the server is accompanied by a header X-ZUMO-AUTH and a token. It appears that this token is issued by the azure app service, not the original provider. It is much longer than the tokens issued by Twitter or Google.
At the same time when I point web-browser at the end-point and go through the log-in process, I see that the browser is using a Cookie: ARRAffinity=c4b66198677464de573103f7aa267c33ea38617020514011cea4506e0a55d9d0; AppServiceAuthSession=EIVymV
Questions:
The problem is Mobile app documentation is it just provides
instructions on how to use the SDK. I am unclear on how I would
obtain the token issued by the app service.
Everyone knows how to obtain access tokens for Google
and Twitter. Can they be used to access Azure API apps?
You are correct that API apps use the same built-in authentication as mobile apps. The basic flow looks like this:
Login to the app using provider credentials. This can be done using either a client-directed flow using your provider's SDK or can be done using a server-directed flow involving browser popups (i.e. the web view you mentioned). In the latter case, there is an endpoint at /.auth/login/ which is provided by App Service and manages the login flow for your app.
App Service will respond to your client app with a session token (a JWT).
You call into your APIs using the session token from #2. It is passed via the x-zumo-auth HTTP request header (it's named this way for legacy reasons).
The AppServiceAuthSession cookie you are seeing is the session cookie for when you use a browser to do authentication. ARRAffinity is an internal routing cookie used by App Service and is not related to auth.
If you're looking for more internal technical details on how the built-in App Service Authentication / Authorization works, check out my blog, starting with this post: http://cgillum.tech/2016/02/01/architecture-of-azure-app-service-authentication-authorization/

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