The importance of securing the cyberspace is higher than ever along with the evolution of cyber attacks launched by hackers with malicious intention. However, there has been little research to understand the hackers who are the most important agents determining the landscape of information security. This paper investigates the behaviors of hackers using a longitudinal dataset of defacement attacks. Based on theories of economics of criminal behaviors and variety seeking, we find that hackers seek variety in choosing their victims in terms of region, hacking method, and the type of operating systems; as their prior experience is focused in terms of hacking methods, target regions or operating systems, they tend to launch more attacks using new hacking methods, or against targets in new regions or using new operating systems. Furthermore, hackers are more likely to seek variety as the time interval between the previous and the current attack becomes longer.