Why PasswordBox is Sealed in Silverlight?

Question

A simple question, but google has no answer on that!
I'm hitting a wall today, because the PasswordBox in Silverlight is Sealed. I have no idea why they do that. Is somebody have an idea on that?

Answer 1

Because if you can subclass it, you can introduce vulnerabilities into it.

Some vulnerabilities that might be introduced:

1. Accessing protected members.
2. Creating special accessors to protected members.
3. 3rd Party Injection - someone else subclasses your class to get at the password.