Germany, On the Application of International Law in Cyberspace (March 2021)

The obligation to take precautions in attack is complemented by the obligation to conduct weapon reviews of any new means or method of cyber warfare to determine whether its employment would, in some or in all circumstances, be prohibited by international law. The findings of such reviews, to the extent that they identify legal constraints for the employment of means and methods in particular operational settings, should serve as a basis for operational planning. However, the means and methods used in cyber warfare are typically tailored to their targets, as they generally involve exploiting vulnerabilities that are specific to the target and the operational context. This entails that the development of means or the adoption of the method will often coincide with the planning of a concrete operation. Thus, the obligation to take precautions in attack and the requirement of a legal review remain separate requirements, but may overlap in substance.

Federal Ministry for Foreign Affairs, On the Application of International Law in Cyberspace: Position Paper (March 2021) 10