Westphalian state system has been deeply affected from the civilianization of the cyber space. It is possible to see the traces of nuclear war and its competition in this new post-Cold War period. The contemporary threats against the cyber space and their vague boundaries could clearly be seen in the examples. Cyber attacks in this new security environment towards long lasting alliance NATO and its members are giving important clues for the future. In this article one discussed defensive measures of NATO for these new threats and the process which determined the cyber security strategies. Upon this cyber defense strategy NATO tries to level the cyber capabilities of its members and takes the necessary steps to achieve this goal. The Lisbon summit endorsed the preparation of a new strategy that includes cyber defense and protection of the critical information infrastructure.