The principle of due diligence is an obligation on States not to knowingly allow the use of their territory for the perpetration of acts contrary to the rights of other States. The duty of diligence was referred to by the International Court of Justice in the Corfu Channel case: every State has the 'obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States'. The duty of diligence can be transposed to cyber activities. This would mean that it imposes a duty on States not to allow their territory to be used for the launch or transit of cyber operations targeting another State. In that perspective, due diligence may constitute an interesting palliative to the problem of attribution. The principle of due diligence in international law is particularly relevant regarding the behaviour of non-state actors, since the principle subjects this behaviour to some limitations imposed by international law by creating a bridge between them and State responsibility.