Wall Street Journal writer Siobhan Gorman reports that spies have managed to not only gain access to critical systems within the United States electrical grid but also plant applications that could damage the system. This is what folks in the security business refer to as a “bad thing.”

Gorman cites U.S. intelligence officers who say the malicious hackers who managed this feat are most likely Chinese or Russian. Representatives from both of those countries strenuously deny any involvement. Then again, if someone came up to me and asked me if I had infiltrated a critical element of a nation’s infrastructure I think I’d say “No sir, please put me down now.” I’m pretty sure espionage isn’t something you own up to just because someone asks you about it.

Still, it’s true that it’s very difficult to prove the hackers have any official affiliation with any nation.