Analysis of the right to self-defense against cyber attacks in terms of international law

Since the beginning of the use of internet and network-based systems has made a very rapid development has become an indispensable part of our lives. Many of the critical infrastructures of the state and the majority of public and private services such as banking work on the internet and network-based systems. For the uninterrupted continuation of these services, the security of these systems has become a priority for national interests. Due to the characteristics of the cyber space, it is difficult to determine whether the critical infrastructure of the state has been attacked or who has done it. For example, cyber attacks against Iran's nuclear fuel enrichment facilities in 2009 were detected by a cyber security company in 2010.The target of the attack is the supervision, control and data collection system in the facilities.These systems, which are used by many states, are used to control and monitor critical infrastructures such as energy production and distribution, water, natural gas and sewage systems. Because of the opportunities provided by the cyber space to the attackers if it was a cyber-attack, it is quite difficult to determine who or by whom this attack was made. Cyber-attack is attributed to the attacker with a high percentage with the techniques developed today. If the attacker is a non-state actor, necessary sanctions are imposed through domestic law. However, if it is an aggressive state, then the situation becomes a bit complicated. According to current international law and customary law, an armed attack on a state gives it a right to self-defense. There is no doubt that the right to self-defense will arise if cyber attacks reach an armed attack level. However, most cyber attacks are not at the level of armed attacks. For this reason, the current law of armed conflict is inadequate in solving cyber problems.In addition, norms related to cyber space, which is a relatively new field, have not been formed and norms formed have not been widely accepted. Since it is not possible for states to conclude an international agreement on cyberspace in the near future, it is the best solution for states to declare their critical cyber infrastructures and their rules of engagement and act in accordance with these rules of engagement until the norms related to cyberspace are developed. Because the survival of the state and the protection of its vital interests may depend on its immediate, strong and aggressive response. Keywords: Critical Infrastructure, Cyber Attack, Self-Defense, Attribution.