26. No State should knowingly allow its territory to be used for acts contrary to the rights of other States.Footnote 20 This also applies in cyberspace. A State that has knowledge of a malicious cyber activity is expected to take all appropriate and reasonably available and feasible steps to stop ongoing or temporally imminent cyber activities that result or would result in significant harmful effects that impact the legal rights of another State. 27. The precise threshold that triggers this expectation will depend on the totality of the circumstances in that situation. This would include whether the State has knowledge of the wrongful acts, its technical and other capacities to detect and stop these acts, and what is reasonable in that case. For example, a State with limited technical capabilities would not likely be expected to respond if it failed to detect a malicious cyber activity emanating from or through cyber infrastructure on its territory. However, once aware, the State would be expected to respond. State Responsibility 28. The international law of State responsibility applies across the whole spectrum of substantive areas of international law, including in cyberspace. It governs such issues as the attribution of internationally wrongful acts to States. It also addresses circumstances precluding wrongfulness, including countermeasures, and possible remedies. The law of State responsibility is not concerned with the legality of the use of force, including in self-defence, which is a separate area of international law. 29. In Canada’s view, this well-established body of international law is not only applicable, but highly relevant in relation to contemporary cyber activities. To date, all publicly known malicious cyber activities have been widely interpreted by States as falling below the threshold (or thresholds) of the threat or use of force or armed attacks. Internationally Wrongful Acts 30. An internationally wrongful act in the cyber context is a cyber-related action or omission that: constitutes a breach of an international legal obligation, whether to another State or the entire international community; and is attributable to a State under international law. 31. International law recognises exceptions to what would otherwise be internationally wrongful acts. Examples include cases of self-defence and countermeasures. Attribution 5/14