What is Armed Attack

The chapter examines the concept of self-defense in international law and cyber operations, focusing on when a cyber operation escalates to a cyber-attack and justifying a state's right to self-defense. The severity of a cyber operation is crucial, as it distinguishes between operations causing significant harm and those causing only economic damage. The chapter also explores the complexities surrounding the involvement of non-state actors in cyber operations, suggesting the ‘unwilling or unable' doctrine for defensive actions against non-state actors. The legitimacy of self-defense is based on the necessity of the response as a last resort and its proportionality to the threat faced.