login to any user account in application

Question

I have a asp.net application which is using form authentication, as this application is going to be online and we are looking for a secret login page by which we can login to any user account with only his username.

Is that possible?

EDIT

Or if there is any way I can read password from sql server aspnet_Users table, If I can convert it into plain text and use a general method to login. That would work for me

Answer 1

You can't "convert" it back. All hash functions are one-way only so there is no way to get original value.

Edit: There are 'rainbow' tables, which is basically dictionary of text-hash mapping. But they won't help you, because passwords are also salted in default Membership implementation.