Abstract
SCADA systems are monitoring and controlling critical infrastructures such as power generation, water supply, transportation networks, and manufacturing facilities. To ensure those vital infrastructures protection, it is necessary to understand all how the systems can be attacked and adopted a viewpoint similar to an attacker for determining weaknesses and hiatus in defenses; Depending on that, we can design countermeasures to thwart attacks against it. Hence, the chances of a successful attack are significantly reduced. Attack trees are providing a formal, systematic way for describing systems security, based on varying attacks. In this paper, we present some of the potential attacks on each part of the SCADA system through a simplified structural attack tree. We also offer the different ways of DDoS attack, for instance, that targeting the "availability" of the SCADA system through attack tree as a threat analysis document.