A Cracker is an individual who breaks into a computer accounts, systems, or networks and intentionally causes harm. A cracker can be doing this for profit, for malicious reasons, for a social cause, or just because the challenge is there. Once inside a system, crackers typically operate without regard to the safety and security of your data, often acting in ways that cause unnecessary harm or destruction.
Some security researchers divide “Crackers” into two groups. A very small portion of self-described “Crackers” are capable of researching, testing, and building proof-of-concept exploit code that “cracks” or compromises a commercial product, computing device, or network. These individuals are few and far between.
The majority of Crackers are simply “Script Kiddies” who purchase other “Hackers” exploit toolkits and run them to gain access to networks, devices, and accounts they are seeking to exploit. This is the larger group of “Crackers”.
Additional Reading: The Top Ten Password-Cracking Techniques Used By Hackers