chapter  1
Introduction
Pages 22

Vulnerabilities in cyberinfrastructure can be attacked horizontally or vertically. Hence, cyber threats can be evaluated horizontally from the perspective of the attacker(s) or vertically from the perspective of the victims. First, we look at cyber threats vertically, from the perspective of the victims. A variety of adversarial agents such as nation-states, criminal organizations, terrorists, hackers, and other malicious users can compromise governmental homeland security through networks.