The existence of secondary rules of responsibility stems from two cumulative elements: a breach of an international obligation and the attribution of this breach to a State. The present chapter analyses the obligations owed by the State responsible for a cyber operation against another State: firstly, if the cyber operation has a continuing character, the responsible State is under the obligation to cease the operation; secondly, the responsible State may have to offer assurances and guarantees of non-repetition if required by the circumstances of the case; and thirdly, the responsible State has to repair the injury resulting from the cyber operation. Finally, it is necessary to examine the question of shared responsibility, which is applicable when multiple States are involved in the cyber operation.