Becoming a professional penetration tester (or pen tester or ethical hacker) can be a major step forward in an IT security career. But before one can get the most well known professional certification for ethical hackers, you need foundational knowledge and at least 2 years of versified IT experience. Before you begin a formal career and path to certification, you'll want to understand the essential technical and behavioral ways that attackers compromise computer security and what tools and techniques the penetration testers will use to discovered weaknesses before the bad guys do.