Complicity in Unlawful Offensive Cyber Operations Under International Law on State Responsibility




aid and assistance, cyber operations, international law, state responsibility


States are increasingly engaging in cybersecurity cooperation activities and providing support to other states in offensive cyber operations. While international cooperation is generally encouraged and many cybersecurity cooperation activities are lawful, there is also a risk of being complicit in the internationally wrongful acts of other states. This paper examines the risk of complicity in offensive cyber operations under international law on aiding or assisting. It argues that, while international law in this context applies to cyber operations by states, existing uncertainties and limitations around the key components of the law on aiding or assisting are compounded by competing interpretations about how international law generally applies to state conduct in cyberspace. The paper consists of four sections. Following the introduction in section one, section two outlines some of the ways in which states are cooperating in relation to cybersecurity and offensive cyber operations. Section three examines the key elements of international law on aiding or assisting as contained within article 16 of the International Law Commission’s Articles on the Responsibility of States for Internationally Wrongful Acts, and the extent to which these apply or are problematised in relation cyber operations. It demonstrates that article 16 adopts a broad approach to what constitutes ‘aiding or assisting’ and this captures various types of activities in support of cyber operations provided the aid or assistance contributes significantly to a wrongful act of another state, the accomplice state has knowledge of the factual circumstances and the illegality of the act by the principal state, and where the accomplice state and principal state are bound by the same legal obligation. Section four concludes by outlining the limits of cooperation in the cyber context and how states can mitigate the risk of complicity in violations of international law.