It seems that every week, computer security organizations are issuing press releases concerning the latest hacker attack. Some sound dangerous, like the "Killer Resume," or mysterious like the "Mstream" distributed denial-of service (DOS) program, or cryptic like the "cde-dtprintinfo" vulnerability. Each announcement represents a new threat that organizations must take seriously if they are to protect themselves, because even a single security hole can make an organization's networks vulnerable to a determined and persistent hacker. The complexity and frequency of these announcements can be overwhelming to organizations, causing them to get lost in the details and to lose sight of the overall landscape of hacking events. This ITL Bulletin addresses the overall picture, trends, and solutions. First, it reviews the most significant computer vulnerabilities and attacks that have occurred in the past 16 months. Next, it discusses both novel and continuing hacking trends. Finally, it summarizes the threats created by these new trends and techniques, and provide guidance on mitigating that threat.