Hacking is the act of identifying and then exploiting weaknesses in a computer system or network, usually to gain unauthorized access to personal or organizational data. Hacking is not always a malicious activity, but the term has mostly negative connotations due to its association with cybercrime.
A hacker is a person who breaks into a computer system. The reasons for hacking can be many: installing malware, stealing or destroying data, disrupting service, and more. Hacking can also be done for ethical reasons, such as trying to find software vulnerabilities so they can be fixed.
Black hat hackers - Black hat hackers are cybercriminals that illegally crack systems with malicious intent. Seeking to gain unauthorized access to computer systems is the definition of black hat hacking. Once a black hat hacker finds a security vulnerability, they try to exploit it, often by implanting a virus or other type of malware such as a trojan.
White hat hackers - White hat hackers, also known as ethical security hackers, identify and fix vulnerabilities. Hacking into systems with the permission of the organizations they hack into, white hat hackers try to uncover system weaknesses in order to fix them and help strengthen overall internet security.
Gray hat hackers - Gray hat hackers may not have the criminal or malicious intent of a black hat hacker, but they also don’t have the prior knowledge or consent of those whose systems they hack into. Nevertheless, when gray hat hackers uncover weaknesses such as zero-day vulnerabilities, they report them rather than fully exploiting them. But gray hat hackers may demand payment in exchange for providing full details of what they uncovered.