In computing, a hacker is any skilled computer expert that uses their technical knowledge to overcome a problem. While "hacker" can refer to any skilled computer programmer, the term has become associated in popular culture with a "security hacker", someone who, with their technical knowledge,.
Security hackers are people involved with circumvention of computer security. Among security hackers, there are several types, including:
White hats are hackers who work to keep data safe from other hackers by finding system vulnerabilities that can be mitigated. White hats are usually employed by the target system's owner and are typically paid (sometimes quite well) for their work. Their work is not illegal because it is done with the system owner's consent.
Black hats or crackers are hackers with malicious intentions. They often steal, exploit, and sell data, and are usually motivated by personal gain. Their work is usually illegal. A cracker is like a black hat hacker,[5] but is specifically someone who is very skilled and tries via hacking to make profits or to benefit, not just to vandalize. Crackers find exploits for system vulnerabilities and often use them to their advantage by either selling the fix to the system owner or selling the exploit to other black hat hackers, who in turn use it to steal information or gain royalties.
Grey hats include those who hack for fun or to troll. They may both fix and exploit vulnerabilities, but usually not for financial gain. Even if not malicious, their work can still be illegal, if done without the target system owner's consent, and grey hats are usually associated with black hat hackers.
Four primary motives have been proposed as possibilities for why hackers attempt to break into computers and networks. First, there is a criminal financial gain to be had when hacking systems with the specific purpose of stealing credit card numbers or manipulating banking systems. Second, many hackers thrive off of increasing their reputation within the hacker subculture and will leave their handles on websites they defaced or leave some other evidence as proof that they were involved in a specific hack. Third, corporate espionage allows companies to acquire information on products or services that can be stolen or used as leverage within the marketplace. And fourth, state-sponsored attacks provide nation states with both wartime and intelligence collection options conducted on, in, or through cyberspace.