Excerpt from RFC 1392
A person who delights in having an intimate understanding of the
internal workings of a system, computers and computer networks in
particular. The term is often misused in a pejorative context,
where "cracker" would be the correct term. See also: cracker.
A cracker is an individual who attempts to access computer systems
without authorization. These individuals are often malicious, as
opposed to hackers, and have many means at their disposal for
breaking into a system. See also: hacker, Computer Emergency
Response Team, Trojan Horse, virus, worm.