You will probably recall from the last article that I mentioned the existence of two methods of authentication and discussed the first one, which is through an HTML form. In this article, the fifth one in an eight-part series, we'll start with the second method of authentication. We'll also discuss how attackers may gain access to your system.

This authentication method uses a simple form to let the user pass in their credentials. Unfortunately, because of its simplicity, this also opens it up to three kinds of attacks - password sniffing, reply attacks and brute force attacks.