Hacker is a person who is able to discover a vulnerability in system and manages to exploit. Hacking means gains unauthorised access into system. There are three types of hackers as given below:
1.White hat hackers
2.Black hat hackers
3.Grey hat hackers
White hat hackers: white hat hackers or penetration tester are ethical hackers. They use the hacking skill for defensive purpose.
Black hat hackers: this category of hackers also known as crackers . They find the vulnerability in system and use the same for offensive purpose.
Grey hat hackers: these are those category of hackers who use their skill for both defensive and offensive purpose.
The majority of people fall in this categories.
Apart from above another type of hackers given below:
Green hat hackers
A cracker (also known as a black hat hacker) is an individual with extensive computer knowledge whose purpose is to breach or bypass internet security or gain access to software. hackers can also be internet security experts hired to find vulnerabilities in systems. These hackers are also known as white hat hackers. Crackers can also refer to those who reverse engineer software and modify it for their own amusement.