Cross site authentication - authentication

I'm just wondering how cross-site authentication is handled for completely external companies?
e.g. My site acts a "portal" onto another completely external site.
Is there a standard way of doing this so the user is not prompted to log in again?
I know with e.g. eBay-> PayPal you have to re-authenticate, but is this the only/most sensible way?

It's going to depend on what that other site uses as an authentication method.
Look at SAML (which in essence a way of saying to the other site that they can trust your assertion that this user is who you say he is). OpenID is another system doing much the same thing.
In general, this is federated identity management,

In my opinion the best way to do this is to create a third application which is responsible for authentication and permissions. I've written a blog entry about one such application I've created for my own pet projects.
http://www.netortech.com/Blog/Entry/12/Web-passport-services

Related

Does it make sense to use OAuth for a native desktop app that owns the resources it uses?

We have a native Windows desktop app that uses resources that we control on behalf of our customers. In the vein of not rolling our security infrastructure I am wondering if it makes sense to use an OAuth library / framework like IdentityServer (our frontend and backend stacks are .NET based with ASP.NET Core on the backend).
But from what I have read OAuth is all about giving an application access to resources that the users owns that are managed and controlled by another party without exposing the user's security credentials to the application.
Given the application is from our point of view "trusted" it seems more straight forward for the application to capture the password directly from the user and obtain an access token (e.g. bearer token) from directly from the back end rather then redirecting the user to the web browser.
Management of authorization levels for various resources is something we need to take care of robustly, as we will have multiple applications and users which will need configurable access levels to different types of resources, so I don't really want to be rolling our own solution for this.
We also want the ability for users to remain logged for indefinite periods of time but to be able to revoke their access via a configuration change on the back end.
Should we be using a different type of framework to help ensure our implementation is sound from a security point of view? If so please any suggestions of suitable technology options would be most helpful.
Alternatively, is there a OAuth flow that makes sense in this case?
It sounds like the "Resource Owner Password Credentials Grant" might help with your problem.
In the short term, the use of oauth may not seem very different from the normally "username password + rbac" based model, but the benefits may come in terms of scalability later on, for example when single sign-on needs to be implemented, or when it comes to the need to provide service interfaces to third parties.

Authenticating external ADFS users in my SAAS application

Our SAAS system is currently using standard Microsoft.AspNet.Identity.Owin libraries to authenticate users via Bearer tokens, as well social logins such as Facebook/Google/Twitter/etc.
Some of our users are asking for us to start allowing of authentication via ADFS.
I'm trying to understand how this can be done. Unfortunately, all of the blogs appear to dive right into the details without providing a good overview as to what's involved. Furthermore, most blogs talk about trusting a specific Active Directory, while we need to trust a whole number of possible customers' active directories - and do it dynamically. IE: customer registers for an account using custom username/password, then provides our SAAS application with some information about their AD. Afterwards, our SAAS application should trust authentication for users in that AD (just the auth part)
Can anyone provide information on what's involved?
TIA
Agree with #vibronet's points.
Another approach would be to add STS support to your SaaS application. This could be either WS-Fed or SAML. You have tagged the question with Azure so AAD could be an option.
You could then federate with any number of other STS's (like ADFS). Note as stated that each ADFS has to agree to add your metadata.
Another approach would be to use IDaaS (e.g. Auth0, Okta). These would do the Identity heavy lifting for you and would essentially provide the STS capability.
The question has 2 parts,
how to work with an ADFS instance and
how to deal with an arbitrary number of ADFS instances from different
owners.
The answer to 1) is to use the WS-Federation middleware, which can be added alongside the middlewares you are already using. However the initialization of that middleware requires knowledge of the location of the metadata document of the ADFS you want to target; furthermore, the ADFS administrator must provision your app explicitly or no tokens will be issued. Hence, the flow you are suggesting (temporary username/password and subsequent details exchange) might be tricky - but not impossible.
About 2) there isn't a way of wiring up an arbitrary number of different ADFS instances unless you modify the middleware setting pretty heavily. The actual answer is that the standard practice for dealing with that scenario is to rely on one intermediary ADFS (or equivalent) that can broker trust toward all others, while your app only needs to trust the intermediary ADFS.

Joomla Security REST API OAuth

I am in the early stages of planning (in particular for the security) of a REST API through which a mobile application authenticates and then sends data to be stored in (and also to be retrieved from) the Joomla website/database. It's basically an application-to-application authentication.
I plan to use the API for own internal use which means that the otherwise important aspect of "making it easy for third party developers/API users" is not as important. My main concern is that I of course want to prevent that illicit information can be injected through such API calls. At some stage I might also be asked by external auditors about how this security aspect is properly covered - hence I better be prepared from the start... ;)
SSL is planned to be used for client/server communication and the API will also use a username/pw for authentication, But does anyone have an opinion about (and maybe experience with) using OAuth as a security layer? I do not mean using user's social media pw for the Joomla login, I mean implementing oAuth on the Joomla Component side (i.e. the Joomla side REST API).
Thanks
This is exactly what we have done at our organization. It would have been nice to follow some existing OAuth (I assume OAuth 2) implementation using Joomla but I don't think it exists other than vanilla php implementation. We used this active project but built our own from scratch. This project takes into account all Grants and I suspect if you are doing mobile app authentication like us you will stick to the Resource Owner Password Credentials Grant. So it really depends on what you are doing.
So the first part was authenticating with Joomla from our mobile app. Here is a post on the start of that. With that we followed the spec RF6749 to follow the convention needed and produced the proper Bearer Token etc.
Then it was a simple matter of doing what was needed for the mobile apps with the REST APIs.
I'm over simplifying it (especially since I'm recommending going through the RFC carefully) but once you know how to authenticate with Joomla, your sailing. IMO.

Implementing "true" Single Sign-On: OpenID, something else, or custom hack?

We're trying to evaluate a solution to implement "true" SSO for multiple (already existing) web solutions. True SSO here means to login on any service, and be authenticated on all, without further actions from the user.
All of the applications we're going to use support OpenID and/or have plugins that allow OpenID, so this seems like something worth looking into. However, as I understand OpenID, the users would still be required to enter their OpenID credentials in each service.
Is there a sane way to implement SSO with automatic login once the OpenID provider has authenticated the user?
In an earlier project, we hacked up the PHP session data in the login procedures of two applications (both running on the same domain and server) so a login in the first application creates the session data for the other application as well. However, this is a very hacky solution and is prone to break when either application is updated, so we're trying to avoid it this time.
Are there any other SSO solutions that we could look into?
i am assuming that you have the control on the SSO implementation
there are some things you can do to make sure that once the user has been recognized by the SSO application, he will virtually automatically be logged in to your other applications
in your SSO application, create a whitelist of service providers. authentication request from those websites will be automatically approved. thus, user won't be asked to approve the request manually
in your application, set the return_to parameter as the page the user is intending to immediately open. don't simply set the return_to to that application homepage
by the way, the most standard openid implementation accepts any url. however, if you want to use the sso in a controlled environment, you can set the service provider to have a whitelist of trusted identity providers. after all, it's the service provider which initiated openid authentication.
Yes, there is a means to do this. Run an Application Server, Node Based, and register cross-domain techniques to offer cookie-credentialed (backed up by site-handshakes as each new user arrives, to scale better and minimize resource expenditure per-session).
I am working on such a beast right now, and I'm 5/6th done.
I have taken care of several annoying variables up front- including the means to assure unique user logon- and I've taken a stand on other issues- one just can't get everything done in one system. However, one can have a true SSO if one is willing to pull out some stops. It is YOUR stops which will define your solution. If you have not accurately portrayed your limitations then there isn't a solution which can be offered for implementation here, and the nature of your problem is ENTIRELY implementation- not theory. In theory you have 4-5 different options. In practice you will find your answers.

SSO Best Practices: What are solutions for unreachable IDP?

Here's something similar to this question on general SSO best-practices. What is the best approach for dealing with a disabled or for-whatever-reason-unreachable central identity provider. If your website allows users to login with their centrally-stored credentials, and the central service is not working or unreachable do you:
Allow users to re-enter their credentials on the local site, so that they can use the native login facility of the web application (or content management system or whatever)
Allow users to request another secondary set of credentials that they can use on the web application itself (i.e., a separate password they can use when the IDP is down) [NOTE: obviously this defeats the 'single credentials' goal just tossing out all ideas].
Allow the users to login using any of several various maintainers of the same credentials (by giving them multiple links to multiple providers, and then trying each one of them until one of them actually connects and works)
For probably apparent reasons, none of these solutions above seem attractive, so feel free to put these on the "worst practices" list while you answer with the best alternative approach.
I'd think the best way would be to have decentralized SSO, as is implemented in Open ID. If each account can have many providers, then if one provider goes down, you can fail over to another.
On the other hand, if centralized SSO is required. The only thing that I can think of would be to have the central authority generate a cryptographic certificate for each user. If the service has a fresh copy of the certificate revocation list and a cached copy of the central authority's public key, it can validate certificates even if the central authority is unavailable. Unfortunately, this method would probably suffer from usability issues as users would need to both keep a copy of their certificate handy and know what you're talking about when you ask for it.