What's the best way to send password from Silverlight to WCF RIA?

Question

I have created Silverlight Login Page. I use PasswordBox in that page and use this solution to do MVVM in my application. BTW after I read this answer I realize that current solution is not secure.

I want to know how can I improve security in my solution even though it will break MVVM.

Answer 1

You should send the password over HTTPS. The Session ID should also be transmitted over HTTPS at all times or you would be violating OWASP A9 - Insufficient Transport Layer Protection.

Answer 2

I always consider my Silverlight applications in the context of the website they're running on. So, if the user logs into the website, I don't want them to have to login again when they get to the Silverlight app that runs from the website.

As such, I do not have a login screen in my Silverlight app. The folder that contains the Silverlight app redirects back to the ASP.Net login page and the user logs in there before ever entering the Silverlight app. Once that is done, the Silverlight app can get the user's details by making a request to the server.