Hacking: It is an act of penetrating computer systems to gain knowledge about the system and how it works. Technically, a hacker is someone who is enthusiastic about computer programming and all things relating to the technical workings of a computer.
Crackers are people who try to gain unauthorized access to computers. This is normally done through the use of a ―backdoor‖ program installed on the machine. A lot of crackers also try to gain access to resources through the use of password cracking software, which tries billions of passwords to find the correct one for accessing a computer.
There are many ways in which a hacker can hack. These are:
• Net BIOS
• ICMP Ping
• RPC. Statd