Share token between different domains - javascript

I'm looking a way to securely share a token between one webapp with the front-end of a second webapp.
Environment details:
webapp.local: A PHP webapp that stories some data that are restricted to specific users. This webapp is accessible by VPN only.
otherwebapp.example: This is a Zendesk instance, it allows us to create a plugin (HTML + JavaScript) that is loaded on the client-side.
Notes:
webapp.local and otherwebapp.example use different domains (they aren't sub-domain).
otherwebapp.example is not able to access the webapp.local. But the front-end will be able (the user are connected to the VPN).
I did some research, and found some options:
HTTP Coockies: the "SameSite" need to be "None" (reference), is it a secure option? I did some tests and seems that they need to be on the same sub-domain.
JS postMessage: It will need to open a popup or a iframe, I did some tests but still trying to make it works.
The question is:
Is there a best practice or another way to share a sensitive data (token) between a webapp and a front-end located on other domain/app?

I think there is not a fully secure way to do it because you want to handle the share on the client side and that will be always exposed, though you can take a different approach like share a request token via GET param to the second webapp and there call a validation API that validates the origin of the request (should be restricted to the second webapp domain) and also validate the passed token and then return the actual session token.

Related

How to make token based authentication when someone open a page directly

There is a sensitive page in my website, so I want to authenticate visitors before they opening a link like: www.examples.com/builder.
I know if I use cookie based authentication everything will be simple, as the browser will send the credential message in cookies automatically. But in my situation, I have to use token based authentication. Browser don't send token if there is no pre-load script.
So my question is how to achieve token based authentication when someone open a sensitive page directly.
As far as I can understand,
you're looking for a way to avoid double roundtrips to send authentication headers to your web-service.
If I am correct, then this would only be possible via service worker which is a not widely supported feature. https://developers.google.com/web/fundamentals/primers/service-workers/
If, depending on your requirements, you can't go for service workers, then, the only left option is to use cookies.
I normally have a secondary authentication flow which uses cookies allowing a web service to authenticate a user on its first get request (the one made by the browser).
There are also some spa framework which implement routing resolvers but this will require a double roundtrip (1. load javascript, 2. send the token).

Proper OAuth2 flow for public first-party clients

I'm a regular reader here at stack overflow but this is my first question.
I'm developing an authorization-server using the OAuth2 specs. And I just got stuck with how do I ensure the first-party client authenticity while using the password flow. I read many forums and this is what I got:
Javascript single-page clients
This blog post by Alex Bilbie, he states that to avoid the client_secret problem we should just:
It’s simple; proxy all of your API calls via a thin server side component. This component (let’s just call it a proxy from here on)
will authenticate ajax requests from the user’s session. The access
and refresh tokens can be stored in an encrypted form in a cookie
which only the proxy can decrypt. The application client credentials
will also be hardcoded into the proxy so they’re not publicly
accessible either.
But now this proxy can be accessed by someone impersonating my
angular app. And then I came across this blog post from Andy
Fielder: How Secure is the OAuth2 Resourc Owner Password Flow
for Single Page Apps. He basically says to rely on CORS to
avoid impersonating JS clients.
It is a good idea to use both approaches to secure my JS app?
Native Apps (Desktop and Mobile)
In the case of mobile apps, I only found cases for Authorization
Code and Implicit flows. This is not what I want, as the redirects
will compromise the user experience. So my thoughts on this is:
I will use the ROP flow and then register the client with a
client_id generated for this particular installation and attach it
to the user account, receiving the access_token and a
client_secret as response. Any other token request made by this
client MUST carry this credentials (as the client_id is specific
for the installation, I will be able to check if this client is
already authenticated). This way if someone uses any credential for
impersonating a client, or even registers a bogus client, I can take
mesures to revoke the user and client access.
I know that this can be overthinking, and I also know that some of this matters doesn't avoid anything. I just feel that is my job to protect my API as much as I can.
I would really appreciate your thoughts about this matters! Am I really overthinking? Should I just use the concept of a 'public client' and carry on?
Thank you all and happy coding!
First of all, this problem is not a common priority because most applications are developed first with website, and after with the API. This is probably the reason because no one knows how to deal first clients with oauth2, because everyone have developed other ways to do that and oauth2 is needed only to grant user access to third party applications.
Even if you have develop the oauth2 authorization server only for your first clients applications (thinking about a single authentication mechanism instead of developing many), you should try to develop the authorization code or implicit grant types. You will realize that you need a way to check what user is actually logged in.
The two common methods are:
user session (based on Cookies)
user access from localStorage (based javascript)
In either ways you need to check your application security, user session is vulnerable to CSRF, localStorage are vulnerable to XSS. There are a lot of articles about how to secure your website against either, so I will not suggest anything here, you just need to know that they exist.
Now that you choose your authentication method we can start to do some consideration about:
Javascript single pages applications
Proxy
Having a proxy that filter all requests in my opinion is like to have a door with the keys always inserted. It's useless even build the door.
However, for session based authentication it's the only way to do it. Allowing session authentication on your Rest API will open to CSRF security issues, so you need to have a proxy layer that get the user session, retrieve the access token from the session and do the request to the Rest API adding the Authorization header.
CORS
With this method you need to store the user access token in the localStorage, because the token is retrieved from the Js client directly.
Using CORS you are sure that other websites cannot do requests to your Rest API from a browser. But your first client need to be public (ie: it does not have a client_secret).
Native Apps (Desktop and Mobile)
In my first application I tried to use the same mechanism that you suggest to secure the auth flow. However that type of mechanism require that you identify every user client in an unique way. This is not possible in iOS for privacy reasons and with some probability it will denied in the future releases of Android. So you should rely on a public client and add only the client_id in your native application code.
This means that your native app client/your js client can be impersonalized? Yes, and there is no way to prevent this with oAuth2 resource owner password credentials grant type.
The main reason about this is because oAuth2 is not for authentication, only for third-party authorization, and that grant type was added only for specific third-party applications trusted enought to use directly the user password. You could read more about this argument here and here.
At the end
You still need a way to auhorize your user, and I think that the best you can achieve using oAuth2 is what Auth0 did.
Essentially this Saas manage your users with an oAuth2 server + OpenID connect, so you are always managing your users like its a third-party application and everything works fine.
Indeed, you can see on this page that for mobile applications they suggest to use a browser based login form, because the native one can be impersonalized by everyone that decompile your application, but if you wrap it into an authorization code flow it works fine.

AngularJS security on authentication

We're developing a system using AngularJS and PHP. I have some concerns about the security on the matter of authentication. I wrote a basic authentication based upon multiple different examples around the web (I only started learning Angular), which uses a database via REST API calls. On some routes it checks if the user information exists before it creates a promise, but I have a few questions:
Can session information be stored in$window.sessionStorage or $cookieStorage without the client being able to modify these values or should I keep them server-side with PHP $_SESSION and fetch them from there, never storing them anywhere in JS? Session information can contain uid, role, email and name
Can I store a value, like let's say $rootScope.role or $scope.role without the client being able to modify this value? Let's say for example we have multiple levels of user accounts where super-admin is the highest. If I create a route with a resolve which would check the $rootScope.rolelevel, can a novice go change the $rootScope.role value to super-admin gaining access to restricted backend sections?
Will I have to implement a GET /session check on every route to which gets $_SESSION data to actually make sure this data stays untouched?
Or am I just paranoid?
You're not paranoid, any client-side authentication should be questioned. When it comes to security, you can't assume that the client is forbidden or unable to do anything on their own device.
Security related functions must stay on the backend, an environment you set up and control.
can a novice go change the $rootScope.role value to super-admin gaining access to restricted backend sections?
Asking questions like "can a novice..." are futile in my opinion. Do you only want security against novice malicious users? If your "restricted backend sections" can be accessed by modifying the frontend, you're doing something wrong.
Great question! Front end security requires the cooperation of the browser and your server.
Javascript is an untrusted environment, so you can’t reliably enforce any authorization there (i.e. you can’t use properties on $scope to prevent a user from doing something). Your server needs to enforce these rules by ensuring that every API request is properly authenticated and authorized.
API requests are typically authenticated with a cookie. The cookie typically contains a session identifier, which points to a row in your database which contains the authorization information (i.e. what the user is allowed to access). The user can get this cookie by logging in (presenting hard credentials like a username and password).
The cookie may also contain a signed access token, such as a JWT. Depending on your architecture you can remove the session database and rely purely on the signed token for authentication.
In either case you want to set the HttpOnly flag on the cookie when your server is sending the cookie to the browser. This will prevent the JavaScript environment from reading the cookie, this is a good security measure to yourself against XSS attacks.
You also need to protect yourself against CSRF attacks. This is a situation where another website can trigger a GET or POST request to your API, and this will send along the authentication cookies. You can guard against this by creating another cookie that does NOT have the HttpOnly flag, and storing a random value in it. The JS environment must attach this value to any request, typically as a custom HTTP header. Your server then asserts that the value is associated with the session or token.
I’ve tried to cover all the bases in this answer. If you’d like to read more, you can check out these blog posts that I’ve written, they discuss token authentication, but each has sections that cover front-end security issues:
Token Based Authentication for Single Page Apps (SPAs)
https://stormpath.com/blog/build-secure-user-interfaces-using-jwts/
Disclaimer: I work at Stormpath and we provide a secure, hosted user management solution for any application, including Angular! See https://docs.stormpath.com to learn more and find the SDK for your server.

Access the force.com REST API with a pure Javascript page

I want to develop a front-end in Javascript (possibly with one of the fancy frameworks around such as AngularJS) that consumes the REST API of my Salesforce org.
I don't want to embed my project in Salesforce technologies, so basically
no Visualforce pages
no Force.com Sites
I do want to write my own front-end on a separate server that just makes AJAX calls to the Salesforce back-end.
In addition, I want the application to be accessible for any user, even if he/she does not have a Salesforce account. So the AJAX calls should not require that the user logs in on Salesforce. I want anonymous users to be able to retrieve public data from my organization and create new entries when it is useful (in the case of a survey for instance).
Even though these requirements generate some security concerns, I can imagine that Salesforce takes care about the requests rate limits on their API endpoints and that it is possible to restrict the access to the API on a host name base (e.g., only requests with origin host my-trusted-domain.com should be allowed, send a 403-Forbidden otherwise). I would be surprised if SF does not provide such basic features.
How would you proceed? Is there a minimal Javascript code that works out-of-the-box on any domain without getting into troubles with CORS?
All REST API calls to Salesforce must be authenticated. If you want anonymous API access then you will need to proxy authenticated calls through a server (like on Heroku) that adds the auth token. Or you can use Heroku Connect to expose your Salesforce data to a Heroku app as a Postrgres database.
If you go the REST route then checkout the ForceServer and my CORS Proxy for Salesforce. Both are not setup out-of-the-box for the anonymous access you are looking for but could easily be tweaked to support that use case.
BTW: When allowing anonymous access to your Salesforce data through a proxy make sure you are dealing correctly with security and request limits.

How to Secure ASP.NET Web API with Cross Domain AJAX Calls?

I want to create an API at www.MyDomain.com that is accessible from public websites www.Customer1.com and www.Customer2.com. These public websites display each customers inventory and do not have any login features. They will use AJAX calls to read data from my API.
How can I secure the API so that it can be accessed via AJAX from different domains but no one can access the API to be able to scrape all of my customers data and all of their inventory?
I have tried thinking of different solutions on my own but they would all either require people to login to the public websites (which isn't an option) or it would require some secret "key" to be displayed publicly in the browser source code which could then be easily stolen.
Any ideas would be greatly appreciated.
Thanks!
P.S. Are their any obstacles that I am going to run into using Javascript & CORS that I need to look into now?
Anything that is accessible without authentication from a browser is by definition insecure, so you can't stop that. Your best bet is to have to have a relationship with the owner of customer1.com and customer2.com - the server apps for those two websites would make an HTTP call to you and authenticate with your service. Going this way also avoids the CORS issues you're talking about.
If you've already designed the client functionality, you can still probably do it without much change to the javascript - have it point to customer1.com for its AJAX call instead of your API, and customer1.com would accept this request and just act as a proxy to your API. Aside from the authentication, the rest of the request and response could just be pass-throughs to your API.
You can use Microsoft.AspNet.WebApi.Cors.
It's just need add ONE line at webapi config to use CORS in ASP.NET WEB API:
config.EnableCors("*","*","*");
View this for detail.
The simplest way to provide a minimum security here is to provide some kind of token system. Each app has its own token, or combination of tokens which it must pass to the server to be verified. How you generate this tokens is up to you and other than being linked to app's access, doesn't have to mean anything.
Provide a way for each API implementer to open an account with you. This way you will know who is accessing what and in some cases you can block/stop service.
For instance, a token can just be an MD5 hash:
7f138a09169b250e9dcb378140907378
In the database, this hash is linked to their account. On each request, they send this token with what they want. It is verified first to be valid, then the request is fore filled. If the token is invalid, then you can decide how to deal with it. Either don't return anything or return an "access denied" (or anything you want).
One thing to avoid is having a single token for everyone, though this can be a starting point. The reason for this is if some unauthorized app gets a hold of this token and exploits it, you have to change the token for everyone, not just the app that somehow leaked the token. You also can't control if someone has access to something or not.
Since you listed ASP.NET, I can also point you to WCF, which is fairly complex but has all the tools that you need to setup a comprehensive web service to service both you and your clients.
I hope this gives you a starting point!
EDIT:
There are security concerns here in the case that someone leaks their token key somehow. Make sure that you setup a way in which the app/your service do not expose the the token in anyway. Also have a flexible way of blocking a token, both by your clients in you, if it so happens that a token is exploited.

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