Interface term is referring to the action of the user to interfere with a software running on a web server. To find some examples on this matter, I suggest that you use Google.
Cookies are small files that are sent from a web server into the user's computer while this one is accessing it. These small files are sent back to the server each time the user access it, and inform the host about the previous activity of the user. It's possible to change a cookie file so a user that is trying to access the server will be blocked, for example. You can also use Google to find out more about this subject.