Medusa is a log-in brute forcer that attempts to gain access to remote services by guessing at the user password. Medusa is capable of attacking a large number of remote services including FTP, HTTP, MySQL, Telnet, VNC, Web Form, and more. In order to use Medusa, you need several pieces of information including the target IP address, a username or username list that you are attempting to log in as, a password or dictionary file containing multiple passwords to use when logging in, and the name of the service you are attempting to authenticate with.
Penetration testing is the legal and authorized attempt to exploit a computer system with the intent of making a network or system more secure. The process includes scanning systems looking for weak spots, and launching attacks and prove that the system is vulnerable to attack from a real hacker.