Situational awareness - the perception of "what's going on" - is crucial in every field of human endeavor, especially so in the cyber world where most of the protections afforded by physical time and distance are taken away. Since ancient times, military science emphasized the importance of preserving your awareness of the battlefield and at the same time preventing your adversary from learning the true situation for as long as possible. Today cyber is officially recognized as a contested military domain like air, land, and sea. Therefore situational awareness in computer networks will be under attacks of military strength and will require military-grade protection. This chapter describes the emerging threats for computer SA, and the potential avenues of defense against them.