To protect business critical networks and applications from a malicious cyber-attack, organizations today often employ Red Teams to challenge and test enterprise system defenses. The Red Team's goal is to covertly seek out vulnerabilities and identify them before the "bad guys" can do any damage. In this report, expert and IT security consultant Nicholas Arvanitis introduces the concept of Red Teams and discuss how they should fit into an organization's overall security plan. In addition we'll learn about some of the common challenges faced when utilizing Red Teams and adversary based security assessments.