A hacker is a person with deep technical skills who finds unconventional ways to use or break computer systems – for defence or for attack.
What the word means
In the 1960s at MIT, “hacker” meant an enthusiast who explores systems in clever ways. Today the word mostly refers to people who find and exploit security weaknesses. Hackers are usually grouped by intent:
- White hat – ethical hackers who test systems with permission: penetration testers, red teams, bug bounty researchers.
- Black hat – criminals who break in for money, data or disruption.
- Grey hat – people who break in without permission but without clear criminal goals, for example to report a flaw.
Among attackers there are further groups: financially motivated cybercriminals and ransomware affiliates, hacktivists with political aims, and state-sponsored APT groups that conduct espionage and sabotage. The term cracker was once used for criminal hackers and today mostly for people who remove copy protection (crack software).
Why hackers matter for security
Hackers are on both sides of the field. Criminal groups break into companies through phishing, stolen passwords and unpatched vulnerabilities; ethical hackers find the same weaknesses first. Bug bounty programmes, coordinated disclosure and CVE identifiers turned security research into a profession. Many laws, such as the US Computer Fraud and Abuse Act, make unauthorised access a crime even with good intentions, so written permission is essential for testing.
Best practices for organisations
- Publish a vulnerability disclosure policy and a
security.txtfile so researchers can report flaws. - Order regular penetration tests or run a bug bounty programme.
- Assume attackers will try: patch quickly, use MFA and monitor for intrusions.
