The basic definition of a hacker is someone who uses a computer system to gain unauthorized access to another system for data or who makes another system unavailable. These hackers will use their skills for a specific goal, such as stealing money, gaining fame by bringing down a computer system, or making a network unavailable -- even sometimes destroying them. However, there are three different types of hackers, each with a particular goal, and not all are the bad guys.
Three types of Hacker
The three types of hackers are the white hat hacker, the grey hat hacker, and the black hat hacker. Each type of hacker hacks for a different reason, a cause, or both. All have the required skills needed to accomplish their mission. At one end of the spectrum is the black hat, who hacks for evil and malicious intent and without permission. On the other end of the spectrum is the white hat, who hacks against a black hat in order to protect computer and network access and has the company's permission to do so. In the middle is the grey hat, who hacks not for evil and not for good; they are neutral in their cause and usually try to sell their skills for monetary gain, like a mercenary.
Black Hat Hacker
The black hat hacker is the one who hacks for malicious intent - he is the bad guy. This type of hacker uses his or her skills to steal money or data, knock a computer system offline, or even destroy them. Some of these hackers love to see their work and name in the news, so they would try to target big name organizations and companies. For instance, they might change the front page of a company website.
Black hats also try to break into computer systems to steal credit card information and possibly steal valuable information to sell on the black market. They may even lock out the computer and network system from the owners and then hold them for ransom.
The black hat works outside of the law. This is the hacker that we as a society are most familiar with. Some black hats have cost companies hundreds of millions of dollars in damages for credit card and social security information theft. They can work alone, in that case known as a lone wolf, or with a team. They work slowly and methodically, since the black hat knows it takes patience to compromise a computer or a network system in order to a hit a big payoff and not be caught.
Have you heard of the hacker group called Anonymous or LulzSec? These are black hat hackers whose goals are more driven for a cause rather than monetary gain are known as hactivists. In 2014, following the Michael Brown shooting in the city of Ferguson, Missouri, a group associated with Anonymous said that they will bring down the city and police servers if protestors were harmed in any way.
White Hat Hacker - Savior
The white hat hacker is one who is an ethical hacker. This type of hacker usually hacks for a company or organization for defensive purposes. The white hat is given special permission with limits on what the hacker can and cannot do on their customer's computer and network systems. This special permission is usually given in a legal document signed by both the white hat and the company, which keeps both parties out of legal trouble.
Grey Hat Hacker
The Grey hat hacker is one who hacks out of curiosity. The grey hat does not align as being a white or black hat hacker. The grey hat usually finds vulnerabilities on their own, such as finding bugs or glitches in software or hardware and then possibly informing the vendor of these vulnerabilities.
Some grey hats hack for the money while others do not. Other grey hats will hack for a cause and justify it for a logical reason. Most grey hats try to use their skills to become independent security consultants. For example, a grey hat may break into a bank's financial system and then inform the bank of what vulnerabilities were exploited. It is possible that the bank may pay the grey hat for their effort because they did find a vulnerability or even offer the grey hat a job; however, it is possible the bank may call the police to have the grey hat arrested for breaking into the bank system without the company's approval. So it is a thin line to walk for the grey hat. The difference between the grey and white hat is having legal permission and authorization.
Article Credit - Study.com