There are many fronts of cyber warfare.
The closest that happened recently is the Chinese hackers getting access to weapon blueprints of the USA (http://goo.gl/pCN8w
) as well as stealing data from the Australian spy HQ (http://goo.gl/uPxJV
). Those are literally war-level compromises.
Also we have the Stuxnet worm which was well designed and targetting Iranian systems,with a payload(amongst other things) to deliver a rootkit at controller level. This was strange and unconventional as it did not target a literal computer-based system...but industrial equipment. The PLC rootkit exposed its true nature as designed by some well-funded, targetting entity. It randomly spun Siemens-based centrifuges that were the exact type used by Iran for enriching its uranium...ie. nuclear process. The affected Iranian labs wasted alot of uranium and time, not knowing that it was an act of sabotage...in the mean time, the US and Israel were secretly in fits of giggles. On another of its fronts, the worm exploited 4 zero-day attacks on Windows. It was a masterpiece...from a security/programming perspective and couldnt have been done by some lone malware developer or a group. It was too elegant.
It had a trail that led to the US and Israel. If you're a security freak, you will find this thoroughly entertaining: http://goo.gl/HIEHQ