The broad objective of this study is to evaluate the vulnerabilities of an organization’s information technology infrastructure, which include hardware and software systems, transmission media, local area networks, wide area networks, enterprise networks, intranets, and its use of the internet to cyber intrusions. To achieve this objective, the paper attempts to explain the importance and the role of social engineering in network intrusions and cyber-theft. It also discusses in vivid detail, the reasons for the rapid expansion of cybercrime. The paper also includes a complete description and definition of social engineering, the role it plays in network intrusion and cyber identity theft, a discussion of the reasons for the rise in cybercrime and their impact on organizations. In closing the authors recommend some preventive measures and possible solutions to the threats and vulnerabilities of social engineering. The paper concludes that while technology has a role to play in reducing the impact of social engineering attacks, the vulnerability resides with human behaviour, human impulses and psychological predispositions. While literature supports the dangers of psychological susceptibilities in social engineering attacks investment in organizational education campaigns offer optimism that social engineering attacks can be reduced.