Philosophical and ethical discussions of warfare are often tied to emerging technologies and techniques. Today we are presented with what many believe is a radical shift in the nature of war-the realization of conflict in the cyberrealm, the so-called fifth domain of warfare. Does an aggressive act in the cyberrealm constitute an act of war? If so, what rules should govern such warfare? Are the standard theories of just war capable of analyzing and assessing this mode of conflict? Upon short reflection, these changing circumstances present us with a series of questions demanding serious attention. Is there such a thing as cyberwarfare? How do the existing rules of engagement and theories from the just war tradition apply to cyberwarfare?