I'm looking for a way to pass some sort of credentials or Authorization token from a VB.Net Client to an ASP.Net web application that allows the Client to auto-login to our Forms-Authenticated website. If a user is logged into a local application, I want them to be able to view some web pages without having to login to the website as well. The credentials are not the same between the apps, but I would just like to pass some sort of encrypted token or key to the web page so I know they are coming from the desktop application. Is this possible without requiring a username and password login?
I also need to make sure this URL that is used cannot be simply copied and used from another location, so I'll need to include some sort of information in the encrypted value to know where it's coming from.
I know how to login the user with Forms Authentication and all that, just need to figure out the best way to secure this. Thanks!
OAuth is commonly used to allow desktop applications to access a user's private data on a web site. Since you're using .NET, I suggest you check out DotNetOpenAuth which includes sample OAuth web sites and client applications. It allows for this secure token to be passed that can tell your web site that the desktop app is the one making the requests and (usually) whose data is being accessed.
The best part about the OAuth solution is your desktop app never has to ask for the user's credentials. No credentials are in the URL. And if the desktop application is ever compromised (perhaps by the computer being stolen), the web site can kill the secure token the desktop app was using to cut off access without requiring the user to change their password.
You might want to look into issuing client-side certificates for these applications. Basically, you generate a certificate that you install with the client application and then on the server side, you check the ClientCertificate property of the HttpRequest instance exposed by the Request property on the current context.
Note that what you are doing is really a very bad idea, in that applications should never be assigned identity, only users. To that end, you should be authenticating each and every user that is using your app, not considering the application to be the identity. It's commonly considered a bad practice to do such a thing.
You can share credentials between the applications using ASP.NET Client Application Services.
Here are some resources:
Client Application Services
Client Application Services with Visual Studio 2008
Is your desktop app running on machines that are in the same domain as your web server (i.e. all in the same company)? If so, Integrated Windows Authentication is your easiest solution.
I think its best idea to use a web browser control inside the desktop application .
Then use the WebBrowser1.Document most probably
WebBrowser1.Document.Cookie
get if the user is singed in.
I also need to make sure this URL that
is used cannot be simply copied and
used from another location, so I'll
need to include some sort of
information in the encrypted value to
know where it's coming from.
If you store the encrypted value in a cookie or as a field in a form (POST request), then the credential is no longer in the URL and so it can't be easily copied (note that I said "easily").
Related
Never thought I'd run into an issue of having too much documentation! I need help with picking the right information so I can read it, understand it, and follow it.
My scenario:
I have an ASP .NET Web Application that is hosted on mywebapp.azurewebsites.net
The web app has a full REST API at mywebapp.azurewebsites.net/api/v1/dostuff/1
You can go to the site and perform all the CRUD stuff. You can also use desktop application to do the same.
I went ahead and enabled Azure AD authentication in Azure Portal. Now in order to do anything on the website, users need to sign in. It brings up the usual Microsoft Login popup and then upon successful authentication redirects back to the site.
But when it comes to the desktop app, I want the users to be able to use it without signing in. Somehow my desktop application needs to be able to make calls to the API/website and be authenticated!
At this point I am lost if there is something I need to do in manifest file, or in the web app, or elsewhere?
Most I was able to do is get an access token using client credentials/client secret.
I just need to know if what I am trying to achieve possible and which document explains the approach of doing so.
Well the fundamental problem you have is that a desktop app (like any public client) has no way of authenticating itself to AAD in a secure way.
You cannot use a client secret.
It is very easy to grab the secret from the executable, and that is basically your app's password.
You would have to make the API accept calls without authentication pretty much.
If authentication is required for access to the API,
then a user must authenticate in the app.
I'm building a mobile application (that might also later become a web application). The server side is a ASP.NET MVC + Web API application and I'm thinking about ways how I could implement the service's user management and authentication.
How should I implement the registration/login screen in the app? Offer native app forms, that will send just API requests to the service or is it preferable to show a web browser component and display the website's login page and then extract a token after the user logs in? I see the first option is more user friendly, but the second one will let me change the login / registration page (like for example adding external authentication providers) without breaking older versions of the app.
My second question is regarding the external authentication providers. ASP.NET Identity has good support for them and it is quite possible to let users register using Facebook or some other OAuth2 provider. Does it make sense to add support for external authentication providers when I plan to expose the app's API publicly? Are there any reasons why that is not a good idea?
Your first option is best if you believe your users will trust you to manage their passwords. You make a secure call to your service, have the service produce a bearer token as the result. That would be an anonymous call. I used the answer from this question to get me going down that path:
Get IPrincipal from OAuth Bearer Token in OWIN
If your users are less likely to trust you with their credentials, then the web view and external provider is a good alternative. You would need to work with providers that support the "Implicit Grant Flow" since don't want to share the apps clientid and client secret on the mobile device. This approach involves using a web view to login in, and then capturing the token on the client uri fragment on the response. I think it is on a location header, but don't have a working example in front of me. Something like:
https://your.domain.com/#access_token = 8473987927394723943294
you would pass that token with each api call afterwards .
Good luck!
I'm developing a web application that requires the user to log in using forms authentication. inside the webpage you need to download a desktop application that requires to login to the same system too. Is there a way to transfer the current logged credentials from the web application to the windows desktop application without need to login again?. Both applications shares a Login object from an vb.net interface.
I tried to save the IP address in the Database but that don't work for me because the website needs to be accessed inside and/or outside of the company and the user cannot login twice in different machines.
I tried to google for solutions but without luck.
Do you have any suggestions regarding this?
This may not be exactly the scenario you're envisioning, but this article shows how to use Forms authentication from a Winforms client using WCF Authentication Services. This should get you going in the right direction. Per the article, you can use these services in any .NET application.
http://msdn.microsoft.com/en-us/library/bb386582.aspx
This article shows how to do it with a Silverlight app, just so you have another example. http://blogs.msdn.com/b/brada/archive/2008/05/03/accessing-the-asp-net-authentication-profile-and-role-service-in-silverlight.aspx
And just one more for fun. http://aspalliance.com/1595_Client_Application_Services__Part_1.all#Page1
There isn't really any way to share this without encrypting a file containing the user's credentials and storing it on the hard drive along with the file, but then you run the risk of someone decrypting the information and getting access to the user's password.
I think that an alternate approach that could work is to generate an authentication token (could be as simple as a GUID) and store it in your database along with the user's id when the user requests the download. You would want this token to expire after a reasonable time limit (5 minutes, for example).
You could then include a file that contains this authentication token with the download. When your apps starts, you could check for the existence of the file. If it's there, you extract the token, delete the file, send the token prior to presenting the user login.
If the token valid, your server would send back the user's login and your app would proceed as though the user were logged in, otherwise you would just display the login screen.
I have a fairly complex business application written in ASP.NET that is deployed on a hosted server. The site uses Forms Authentication, and there are about a dozen different roles defined. Employees and customers are both users of the application.
Now I have the requirement to develop a Windows Mobile client for the application that allows a very specialized set of tasks to be performed from a device, as opposed to a browser on a laptop. The client wants to increase productivity with this measure. Only employees will use this application.
I feel that it would make sense to re-use the security infrastructure that is already in place. The client does not need offline capability.
My thought is to deploy a set of web services to a folder of the existing site that only the new role "web service" has access to, and to use Forms Authentication (from a Windows Mobile 5/.Net 3.5 client).
I did see this question and I am aware of the limitations that Forms Authentication poses. Since security is not my primary motivator (I use SSL and can restrict access by IP address), but rather using existing user accounts and roles, my decision tree is somewhat different as well.
Can I do this, is it a good idea, and are there any code examples/references that you can point me to?
I ended up with a combination of things. First, forms authentication does not really work in this scenario, because of the redirects that you get when a users is not logged in or the credentials are incorrect.
Because I want to use the user accounts from the web app, I worked around this by just calling Membership.ValidateUser prior to processing each service call on the server.
A user is prompted for an id and password when logging on to the client. I store both values encrypted in the proxy class and pass them transparently with each call using a host header, so that the application does not have to bother with this once the user is logged in, i.e. the credentials were validated once by calling the Login() service method (which only calls Membership.ValidateUser).
I use the CryptoApi on both the server and the client side.
I understand that host headers are somewhat outdated for security applications, but since I use strong encryption AND SSL, it is perfectly adequate.
I am in the process of writing an application that will need multiple forms of authentication.
The application will need to support authentication to Active Directory, but be able to fail back to a SQL Membership Provider if the user is not in Active Directory. We can handle the failing to the SQL Provider in code based on the username provided because the username will be a different format than the Active Directory username.
Is this even possible? What I mean is, can I use membership and use both ActiveDirectoryMembershipProvider and SqlMembershipProvider together or will I have to roll my own?
Another additional added complexity is that I would like to automatically authenticate my internal users based of Windows Authentication back to AD, but use Forms Authentication for users not on our internal network, or users that are using the SQL Provider.
These will most likely be separate servers, one internal, and the other external so I have a lot of planning to do to figure out the data replication, and how I will authenticate the AD users if they hit the outside server etc.
I am wondering what thoughts are out there as I start down this road. Is what I am wanting to do even possible without me rolling my own, or is there a way to mesh these together?
Thanks for the reply.
The reason I asked originally was because I was able to get this specific senerio working about 7 years ago using IIS to authenticate and then passing back the credentials to a Lotus Domino Server Web App. If the user was not authenticated via the Windows Authentication/ISS then Domino would handle the authentication. This was what I was looking to do here, but really couldn't think of a way to make it work in IIS.
As for the rest of your reply, I think you are on to the way that I will need to take. I have thought this through and tossed it around in my head a lot. The application will be somewhat different on the two servers anyway since there is going to be limited access to the data on the external server anyway. The fact that so much is going to be different already I may just treat these as two applications, thus negating the need to use two types of authentication in the same application anyway.
I am playing around with the idea already of writing my own authentication/login window for the external server, and if the user trys to log in with their AD credentials on the external server I will be able to detect that and redirect them to the internal server. If they are not on the local network or VPN'd in they will simply not get access. This part still has some thought process to go though so I am not sure.
As an additional thought - is there a way to pull just enough of AD into a SQL database to allow me to authenticate users to the SQL database from the external server using their AD credentials, without creating any security issues? I hope I am clearly typing what I am thinking....
Thanks again!
Tim
This is the way I've handled a similar situation based on this info:
Configured the application to use Forms authentication.
Set the LoginUrl to a page called WinLogin.aspx.
In WinLogin.aspx, use Request.ServerVariables["LOGON_USER"] to get the username then call FormsAuthentication.RedirectFromLoginPage( authorizedUserName, false ) to log them in. I guess you can manually check Active Directory as this point as well.
Create an html page that redirects to a page called Login.aspx
Login.aspx is your standard username/password login.
In IIS, Enable Integrated Authentication and Anonymous on the entire site, but deny anonymous access to WinLogin.aspx.
In IIS, set your 401 errors to the page created in step 3.
What basically happens is that when an unauthenicated user hits the site, they're redirected to WinLogin.aspx. Since anonymous is turned off, integrated security makes a check. If that passes, your custom code in WinLogin can run. If the integrated security check fails, a 401 error occurs. Your custom 401 page redirects to Login.aspx where the user can log in using their username and password with the SQL provider.
As far as I know, Web Applications are configured to use either Windows Authentication or Forms Authentication, but not both. Therefore, I do not believe it is possible to automatically authenticate internal users while requiring others to enter a username / password.
You could authenticate to Active Directory or a SQL user store via Forms authentication by using a custom provider. However, the AD users would still need to enter their username and password. Although I've never combined these two methods, I have used Forms authentication to authenticate against both sources at one time or another.
With that said, I think you may want to consider reducing the "flexibility" of your system. If you have an external facing server and an internal facing server, you could simply change the provider configuration on each copy of the application to go against a different source. Then, you could configure the internal one to use Windows (automatic) authentication and the external one to use Forms authentication.
IMHO, I believe that internal users should not be using the external server to access the application. If they are, they should have a user account stored in SQL, completely separated from their AD account. Basically, when someone accesses the application externally, they are acting as an external user, irregardless of their physical location.
Well, it is possible to use ActiveDirectoryMembershipProvider and SqlMembershipProvider, but this requires you design your log on page with your own code instead of the Login controls.
About the mix authentication (Windows and Forms), as far as I know only IIS 7 makes it easy and clean. See this post for details,
http://mvolo.com/blogs/serverside/archive/2008/02/11/IIS-7.0-Two_2D00_Level-Authentication-with-Forms-Authentication-and-Windows-Authentication.aspx