Crackers
People who maliciously break into information systems and intentionally cause harm in doing so. (e.g., South-African-Teens) (e.g., KC-cracker-Havok)
Complexity: These people have tools similar to those of hackers, but they use these tools for malicious purposes and can sometimes cause a great deal of harm. They are often bold, and often exploit indirect links to make it hard to trace them back to their source.