Security experts say efforts to strengthen critical infrastructure targets continue to focus on front-end systems. The Stuxnet worm that last year showed how flaws in control systems can be exploited to cause damage to physical assets. The issue has been longstanding within the industrial control system (ICS) community. The bigger threats really are the control system flaws that allow attackers to send commands that cause physical equipment to shut down, overheat or blow-up, experts say. The real focus has to be on coming up with a contingency plan in the event of an attack, they say.”]