Technological advancement has undergone a huge transformation in old forms of attack in such a way that various news is heard about the attacks by governmental and non-governmental actors towards the fundamental foundations of another country’s life and not necessarily the tangible borders of that land. Given that many types of modern attacks meet the criteria of aggression and on the other hand in 2010 after years of doubt and speculation states have agreed on the definition of aggression in Kampala and have drawn up an agreement and it is unlikely over the next few decades we can hope for the formation of a document to legalize these attacks one can optimistically believe that the Kampala document has such a capacity to solve the problem of legal vacuum in these years although it is not the final solution. By validating the hypothesis of the realization of aggression in cyber space, self-defense is raised against it by the violated country which can be resolved by resorting to existing rules such as Article 51 of the Charter of the United Nations and the Tallinn Guidelines in such a way that cyber-attacks must necessarily fulfill the criteria of the threshold i.e. character, gravity and scale, be consider as an armed attack and be placed within the scope of the concept of force included in the article 2(4) Charter of the United Nations. Legal requirements of self-defense such as ‘necessity’ and ‘proportionality’ should be observed towards off a ‘present’ or ‘imminent’ danger of armed cyber aggression; however, things like the variety of attackers in the cyber space and collision of non-territorial borders can make the issue of self-defense subject to new bumps