The US Military is preparing for future conflicts that may spill into cyber warfare.

Military needs hackers, StratCom chief says - Army Times

In addition to defending and maintaining the military’s networks during an attack, Chilton said, the military needs to develop offensive capabilities — not only across computer networks but in the domains of space, air, land and sea.

Chilton said StratCom has been asked to plan for how to conduct these “cross-domain” attacks as well as offensive cyber operations. Recommendation for the move was included in this year’s National Military Strategy for Cyberspace Operations.
But there appears to be little hackers can do to defend our networks from the dreaded EMP.

The most devastating sort of cyber attack on the U.S. would involve a decidedly kinetic weapon — a nuclear bomb, detonated high over the Earth. Such an explosion would shut down all but the most “hardened” networks and computers within range; the Pentagon has hardened its most critical structures and weapons systems, such as nuclear-capable B-52 bombers, for such an eventuality.
Read more for some interesting insight on military-grade network security.