The paper addresses several issues in the morality of cyberwar and cyberwarfare, defined as one nation's attacks on the governmental or civilian information systems of another nation. It sketches the diverse technical ways in which an attack may occur, including denial-of-service attacks and the insertion of various forms of malware. It argues that existing international law and widely discussed principles of Just War Theory do not straightforwardly apply to cyberwarfare, and many forms of cyberwarfare differ from previous forms of warfare (...) in neither injuring nor killing human beings, nor causing lasting physical damage ? but can nevertheless cause serious harm to a nation's vital interests. Another dissimilarity with traditional warfare is in the degree of knowledge of the identity of an attacker (the ?attribution problem?). The paper argues that cyberwarfare is not amenable to regulation by international pacts and that we can expect long periods of low-level, multilateral cyberwarfare, a Cyber Cold War, as a game-theoretic equilibrium is sought,. The paper laments the lack of a cyberwarfare policy, and concludes that it is only by applying game-theoretic principles that strategies can be discovered that are both moral and effective in suppressing overall harm to all parties in the long run. (shrink)