A security hacker is someone who seeks to breach defenses and exploit weaknesses in a computer system or network.
HACKING THE SECURITY FOOTAGE! by McJuggerNuggets
Hackers may be motivated by a multitude of reasons, such as profit, protest, challenge, recreation, or to evaluate system weaknesses to assist in formulating defenses against potential hackers.
In computing, a hacker is any highly skilled computer expert capable of breaking into computer systems and networks using bugs and exploits.
Watch hackers break into the US power grid by Tech Insider
The subculture that has evolved around hackers is often referred to as the computer underground.
There is a longstanding controversy about the term's true meaning.
In this controversy, the term hacker is reclaimed by computer programmers who argue that it refers simply to someone with an advanced understanding of computers and computer networks, and that cracker is the more appropriate term for those who break into computers, whether computer criminal or computer security expert.
A 2014 article concluded that "...
the black-hat meaning still prevails among the general public".