Spelling note: you will sometimes see the "hacker" term spelled creatively in different ways, such as "haxor", "Hax0r", and "H4X0R".
Historically, a hacker of the 1980's was strictly evil and dishonest: a criminal who would illegally and unethically take control of computers and networks. And indeed, that criminal definition still applies to some of the hackers today in the 21st century. However, the term hacker has also broadened to include non-criminal and even noble computer users. Today, "hacker" is a moniker that subdivides into "black hat", "white hat", and "grey hat" computer users.
There are 3 types of modern hackers:
- Black Hats: Criminal Hackers. Common job: Penetration Tester.
- White Hats: Ethical Hackers. Common job: Network Security Specialist.
- Grey Hats: Deals in both of the above (jack of all trades, master of none).
1) Classic "Black Hat" Hackers = Criminals/Lawbreakers
This is the classic definition of a hacker: a computer user who willfully seeks to vandalize or commit theft on other people's networks. This classic hacker is also known as a "black hat hacker" because of his malicious motivations. Black hats are gifted but unethical computer users who are motivated by feelings of power and petty revenge. They are electronic thugs, in every sense of the word, and share the same personality traits as punk teens who smash bus stop windows for personal satisfaction.
Black hat hackers are renowned for the following common cybercrimes:
- DOS/DDOS attacks that overload Internet servers.
- Defacing websites by hijacking control and replacing the main page photos with rude slogans. (see example here)
- Performing identity theft by stealing private information of individuals.
- Botnetting: taking remote control of dozens of personal computers, and programming them to "zombie" as spam broadcasters.
2) White Hat "Ethical Hackers" = Network Security Specialists
Different from the classic black hat hackers, white hat hackers have honorable, or at least benign, motivations. A white hat "ethical hacker" is a talented computer security user employed to help protect computer networks. These white hats are not unlike former convicts who take on work as store security guards. While they themselves may not be completely ethical, their vocation is considered white hat. Ethical hackers are usually motivated by a steady paycheck. It is not surprising to see ethical hackers spending those paychecks on very expensive personal computers in their personal lives, so they can play online games after work. As long as they have a good-paying job to support their personal habits, an ethical hacker is usually not motivated to destroy nor steal from their employer.
Related: White Hat "Academic Hackers" = Creative Computer Artists
Another kind of white hat is the "academic hacker": a computer artisan who is not interested in protecting systems, but rather in creating clever programs and beautiful interfaces. If you are an academic hacker, for example, you will take existing programmatic code, and improve upon it through clever alterations and additions. "Academic hacking" is about obsessively innovating computer code so that it becomes more beautiful or more efficient as a program. Academic hackers, in general, are harmless and do not seek to hurt other people's networks. Academic white hats are often graduate students in computer programming.
3) Grey Hat Hackers = Uncertain which side of the law to stand for.
Grey hats are often "hobby hackers": users with basic or intermediate tech skills who like to disassemble and modify their own computers for hobby pleasure, and who also dabble in minor white collar crimes, like file-sharing movies or cracking software. Yes, millions of p2p downloaders are hobby hackers. And indeed, if you have ever modified your router and firewall to allow faster p2p downloads, you could describe yourself as a "grey hat" hobby hacker. Gratefully, only a small percentage of hobby hackers ever escalate into becoming serious black hat hackers.
Question: are you a white hat or grey hat hobby hacker?
Answer: if you obsessively tinker with your computer hardware and software, the answer is yes, you are a white hat hobby hacker. If you obsessively tinker and you like to dabble in breaking software locks and music copyright, then you are a grey hat hobby hacker. In 2010, this connotation is not a negative thing.
Related: the Best Hacker Movies (see black hat and white hat hackers in dramatized action)