Develop Reference

Spa app w/ Web API security concern. Can a logged in user with a JWT make random requests to API

I have a security concern about building a SPA application.
What is stopping an end user to make calls to my Web API as long as they have a token?
For example: I am an end user to a Spa web application and I login through the login form. Get access to the JWT token provided to me (assuming this is easy). Then open up postman and try making every call possible putting that token in the header of every request.
I am assuming the only calls I would be able to make are the ones I would be authorized to make through the UI due to Web API authorization.
Is there any type of security out there to prevent this or is it basically just make sure your Web API has proper authorization?

There is absolutely no difference here to regular websites/web applications. Yes, anyone can try to make any HTTP calls they wish to your server. That holds for plain websites, jQuery sites, SPA sites, mobile applications or Flash games. Your server needs to do the proper authorisation and validation to ensure the user is allowed to do what they're attempting to do.

Calling AAD Authenticated Azure function from Javascript without ADAL? No Access-control-allow-origin header is present

Is it possible to call an AAD authenticated Azure function from javascript without an auth library like ADAL and also without registering the client application with Microsoft?
Getting this error: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '
Both the simple web client app and azure function are registered under the same AAD. Both have the azurewebsites.net domain.
What's the lightest web client we can have?

The error you are getting is coming from a cross-origin resource sharing (CORS) check. I suspect this occurs when calling the function from the web app. The idea is that the browser is making an OPTIONS request first to see if the caller (the web app) is allowed to make a call a resource on a different domain (the function app). If that's approved, then it will make the actual call to the function.
So, we just have to make it so that the function app responds letting the browser know the call is allowed. Fortunately, Functions has a built-in CORS feature. In the portal, select Platform features for your function app. Under the API section, you'll see a CORS option. Add the domain for your function app and click Save. You should see the Access-Control-Allow-Origin error go away.
As for AAD, any OpenID Connect client library would work - ADAL is a fine choice for this, though. You may still need to create a client registration, though.

In Azure AD ,with the normal OpenID Connect/OAuth flow, you would acquire token by making a request to the /token endpoint. However, the azure ad endpoint does not support CORS requests, so making AJAX calls to get access tokens is out of the question. Instead, you can use the implicit flow in a hidden iframe to get new tokens for web APIs . See document here and here for more details .
And yes,i would suggest you use ADAL.JS which helps you to use Azure AD for handling authentication easier .

securing CORS: is there a security scheme with cookies?

I have two web-servers responding on two different ports. I have the main web server that serves a website with a lot of javascript behind HTTP digest authentication, the secondary webserver only executes CGIs that can be directly accessed, always by using HTTP digest, or that can accessed with CORS by the ajax requests related to the main webserver. Both servers share the same users credentials.
My problem is that I don't want the browser to prompt for credentials when the javascript is making requests to the secondary webserver.
I came out with the idea that I could add some special header in the ajax request to the secondary web-server, and if this header is present I can ignore the HTTP authentication. Since the servers share the users credentials, if the user is able to log in into the main web-server, he'll be able to login into the second one as well.
Using a fixed header is of course useless. So the question is: is there a mechanism in CORS to tell the secondary webserver that the user is already authenticated in the first one? Something like a safe way to exchange tokens in cookies?

If it is only the ports that are different cookies will be shared across these origins. So if you know for sure that a cookie is set once the user accesses origin 1, they will be included in requests to origin 2, as long as (assuming you're using XMLHttpRequest) withCredentials is set to true.
Now of course those cookies should contain some authentication data that you verify before you let them bypass HTTP authentication.
And hopefully you're using HTTPS so that the credentials are safe from network attackers.

I'm not sure this has anything to do with CORS. What you need is a single-sign-on solution for the two different servers. You could implement a full-blown OAuth solution, or write a simple one yourself.
For a simple token-based authentication, you'd do the following:
When the user logs into your website, send down a expiring token (over SSL) that grants the user access to the web service.
Take the token and do a GET request to a non-authenticated endpoint in the web service. If the token is valid and non-expired, send an authentication token back to the browser.
As long as your web service implements HTTP authentication properly, the cookie will be set and the service calls won't prompt for credentials.

What is the correct CORS entry for limiting an http:// connection to a remote, hosted web server from a grunt web server on a home network?

I've setup a remote, hosted javascript server (DreamFactory Server http://www.dreamfactory.com/) that responds via REST API's.
Locally, I'm running an Angularjs application through the grunt web server via $grunt serve
https://www.npmjs.com/package/grunt-serve
I have setup CORS on the remote server to allow '*' for multiple http:// connection types. THIS WORKS CORRECTLY.
My question is how I can limit the CORS configuration to only allow a connection from my home, grunt web server?
I've tried to create an entry for "localhost", "127.0.0.1", also my home Internet IP that is reported from whatismyip.com, the dns entry that my provider lists for my home IP when I ping it, a dyndns entry that I create for my home internet IP... None of them work, except for '*' (which allows any site to connect).
I think it is an educational issue for me to understand what that CORS entry should look like to allow ONLY a connection from my home web server.
Is this possible? If so, what and where should I be checking in order to find the correct entry to clear in the CORS configuration?
-Brian

To work and actually apply restrictions, the client requesting the connection must support and enforce CORS. In an odd sort of way (from a security point of view), restricting access using CORS requires a self-policing client (one that follows the prescribed access rules). This works for modern browsers as they all follow the rules so it generally works for applications that are served through a browser.
But, CORS access restrictions do not prevent other types of clients (such as any random script in any language) from accessing your API.
In other words, CORS is really about access rules from web pages that are enforced by the local browser. It doesn't sound like your grunt/angular code would necessarily be something that implements and enforces CORS.
If you really want to prevent other systems from accessing your DreamFactory Server, then you will need to implement some server-side access restrictions in the API server itself.
If you just have one client accessing it and that client is using "protected" code that is not public, then you could just implement a password or some sort of logon credentials and your one client would be the only client that would have the logon credentials.
If the access is always from one particular fixed IP address, you could refuse connections on your server from any IP address that was not in a config file you maintained.

You can't secure an API with CORS, for that you will need to implement an authentication scheme on your server. There's essentially 4 steps to do this.
Update the headers your server sends with a few additional Access-control statements.
Tell Angular to allow cross-domain requests.
Pass credentials in your API calls from Angular.
Implement an HTTP Authentication scheme on your web server or in your API code.
This post by Georgi Naumov is a good place to look for details of an implementation in Angular and PHP.
AngularJS $http, CORS and http authentication

Authenticate client-side app to REST API using CORS with local strategy

The Problem:
Serving a secure API to a client side app using only a local authentication strategy. The red arrows are part of the knowledge gap.
Context:
That is --- client.example.com is making a POST to api.example.com/login where on success client.example.com can gain access to a GET service like api.example.com/secret.
An idea!
Implimentation of OAuth 2.0 with hybrid grant type sitting in front of API.
Why hybrid?
It wouldn't be an Implicit Grant Flow aka Client-Side Web Applications Flow because there is no redirection to API server too grant access token. (i.e.) "Is it ok for so-and-so to access your data?"
It wouldn't be a Resource Owner Password Flow because a Client ID and Client Secret are passed along with the request so it's assumed the client app is server-side.
OK... so what about a little bit of both?
What if we used a CRSF token on page load of client-side app, and POST it with user credentials too OAuth 2.0 authentication endpoint to exchange for access token? You would authenticate each subsequent request with the access token and CRSF token after a successful login.
A good Node.js OAuth 2.0 library I found:
https://github.com/ammmir/node-oauth2-provider
Help Me!
I can not find a working example of an authentication measure that solves this problem! Point me in the right direction?
Ultimately, the goal here is too authenticate a client side app to a REST api using CORS with a local strategy --- i.e. username & password --- even if the convention above isn't possible.
To Accommodate Bounty:
This is a client side app, so let's stay trendy.
I'm looking for a working example using the Node.js OAuth 2.0 seed above for the API/Auth server and a front end framework like Angular.js or Backbone.js to make requests.
The example should match the context described above.

I'm working on an app with a pretty similar architecture though the services are .NET Web API rather than Node and we're using DotNetOpenAuth for the OAuth provider. Rather than the hybrid approach you're suggesting we're doing the following:
x.com serves up a login page
login page POSTs back credentials to x.com
server side logic at x.com combines client_id and client_secret with the credentials to submit a token request (resource owner password credentials grant that you've
mentioned above) receiving back both a temporary access token and a
refresh token
the refresh token is encrypted into a cookie issued by x.com
both the cookie (with encrypted refresh token) and the temporary access token are then sent to the browser
the client app (angular in my case) can now use the access token to hit api.x.com for services (It appears you're well aware of the limitations of CORS... we hacked a version of angular's $resource to facilitate this but it wasn't pretty since we wanted to use all HTTP verbs and support IE9)
when the access token expires, the client side app can request a new access token from x.com
server-side, x.com decrypts the cookie to get at the refresh token and issues another oauth call for a new access token
This is fairly high-level but hopefully gives you a sense for how to tackle your situation. In my case, and it appears in yours, we didn't want to use session state or a database to store the refresh token but obviously exposing that to the browser introduces security concerns so the encryption of the refresh token is important (among other security considerations) and the use of the cookie eliminates the need for session state or other persistent storage on x.com.

Not an answer running for the prize. Just my 2 cents :)
On my web server,
I do my authentication through a rest call with login/password with basic authentication over https. This call delivers a key to the client (a one page web app).
Then every subsequent REST call is signed with the key. The server checks that the signature is correct and everything still happen in https.
This mechanism is quite used I believe.
I don't see the issue with cross domain. I have a single source anf if I need something from another source, I'd use JSONP.
I use nginx as an https->http forwarder.
Not sure how it competes with an OAuth2 solution.

I've built this example using Node and PassportJS to show how to authenticate the users with Facebook or Local Strategy. Both sides are on different domains as you described and it requires CORS enabled.
GitHub: https://github.com/pablodenadai/Corsnection
Live demo: http://corsnection-client.herokuapp.com/

I can't promise that I have time to write working example but I can show you 2 paths :)
The biggest deal is CORS. After you solve that problem it is easy to use $http service. So, first and probably easiest may be to configure reverse proxy in x.com webserver which points to api.x.com. I wrote article here
Second approach is better, and created for exactly this purpose, to authorise specific domain to use your resource. It involves a bit of coding in api.x.com so you don't have to change anything in new web applications served in other domains. You simply need to authorise CORS requests in api.x.com service.
Create table in database where you can manage list of authorised domains
Add in that table record "x.com"
in api.x.com add request filter/interceptor what ever tech term you use for method which should be invoked after request is handled and add in response Access-Control-Allow-Origin: x.com if request comes from x.com (in other words check in request header refer value match to any value in table above and put that value in Access-Control-Allow-Origin response header).
That is all :) After this if you know how to use $http or jQuey.ajax you will be able to POST/PUT/DELETE/... any request to api.x.com from any authorised domain in just few minutes.

I very similar idea using vinilla js web app and cross domain authentication to GAE backend or OpenID connect.
The web app is run on CDN. When click login link, it goes to respective login server and redirect back to the web app (with XSRF security token and HTTPS only cookie). Login server accept cross domain request with credentials. XSRF token has to be set (in header) with every request. cookie is set by the browser. Since it is HTTP only cookie, JS cannot read it. The technique is very secure.
Once login, you can get secure assess from login server.
For detail description, you can find here and open source repo here.