An ethical hacker is usually employed by an organization who trusts him or her to
attempt to penetrate networks and/or computer systems , using the same methods as a
hacker , for the purpose of finding and fixing computer security vulnerabilities .
Unauthorized hacking (i.e. , gaining access to computer systems without prior
authorization from the owner) is a crime in most countries , but penetration testing
done by request of the owner of the victim system(s) or network(s) is not.