A man on a computer

The man in charge of America's cyber operations said that on a scale of one to 10, the nation's preparedness to deal with a major cyber attack on critical infrastructure sits at a dismal three.

"Somebody who finds vulnerability in our infrastructure could cause tremendous problems," Army Gen. Keith Alexander, Director of the National Security Agency and chief of U.S. Cyber Command, told audience members at the Aspen Institute's annual security forum late Thursday, according to multiple reports. Alexander said that since 2009, attempted cyber attacks on the nation's infrastructure systems have risen seventeen-fold, reports ABC News.

"I'm worried most about power. I'm worried about water. I think those are the ones that need the most help," he said.

Top current and former U.S. security officials have for years been decrying vulnerabilities in the computer networks of critical infrastructure industries from water treatment centres to electric power plants -- largely facilities owned and operated by private entities. In his remarks, Alexander reportedly pushed for greater role of government, specifically the Department of Homeland Security, in regulating security measures across industries.

Two years ago, computer experts discovered Stuxnet, a cyber weapon of unprecedented power and complexity that was apparently designed to damage an Iranian nuclear facility. The worm had demonstrated what computer experts had long though possible but had never actually seen: computer code that was no longer confined to disrupting computer systems internally but could reach out and physically alter how a facility works, or potentially destroy it.

Before the worm was alleged to have been a creation of a joint U.S.-Israeli cyber operation, other U.S. officials quickly realized that such a powerful cyber tool may be turned on the homeland. In a Senate Homeland Security committee hearing in November 2010, committee chairman Joe Lieberman (D.-Connecticut) warned the worm could be used as a "blueprint" for other "malicious hackers."

Richard Clarke, former White House counterterrorism advisor, cyber security expert and ABC News consultant, said in January that since Stuxnet was a "plug-and-play" worm, other hackers or foreign governments could take it, modify it and turn it against the U.S.