This article argues that the traditional jus ad bellum and jus in bello criteria are fully capable of providing the ethical guidance needed to legitimately conduct military cyber operations. The first part examines the criteria’s foundations by focusing on the notion of liability to defensive harm worked out by revisionist just war thinkers. The second part critiques the necessity of alternative frameworks, which its proponents assert are required to at least supplement the traditional just war criteria. Using the latter, the (...) third part evaluates ethical issues germane to responding to cyber force, including casus belli, moral aspects of “the attribution problem,” and respective rights and duties when attacks involve innocent third-party states. The fourth part addresses in bello issues, including compliance with discrimination, necessity, and civilian due care imperatives; whether civilians may be targeted with sub-“use of force” cyber-attacks and the permissibility of using civilian contractors to conduct cyber-attacks. Throughout these analyses, conclusions are brought into conversation with those of The Tallinn Manual on the International Law Applicable to Cyber Warfare. (shrink)