If the big dictionaries are any guide, most people who speak English consider a cracker something you eat with cheese, or get prizes out of at a child's birthday bash. The average person would probably be confused. In the rest of the world, people generally refer to those who break into computers as hackers. This may explain why the RCMP, FBI, U.S. attorney general's office, and others described February's assailants as hackers . By the way, purists have argued that if you launch an attack against a Web site without actually busting through a security wall you're not really a cracker since you haven't slipped inside.
Words come and go.
And many, if not most, words wind up with more than one meaning, which is referred to as polysemy. When the meanings are contradictory you have a contronym. For centuries, hacker has been polysemic. Its meanings have included someone who cuts wood, coughs, stammers, breaks up land with a mattock, or plays golf poorly. Nobody owns the word.