Internet has opened a new world. It is a manifestation of never-ending innovation and creativity. It is a source of information, a social platform, and a business network but Information security has become one of the most important concepts in our information and technology driven world. Cyber criminals have evolved several techniques to threat privacy and integrity of bank accounts, businesses, and organizations database. Hacking is usually done to gain unauthorized access to a computer system or a computer network, either to harm the systems or to steal sensitive information available on the computer. White hat hacking is an exciting concept where the premise is that if you want to catch a criminal you must be able to think like one to stay one step ahead. This paper describes what is ethical hacking, what are the types of Hackers, hacking history, techniques used in hacking.