“What threat to the banks, utility companies, and telecommunications companies that make up the ‘critical online infrastructure’ of the United States worries one of the Pentagon’s top cyber officials more than almost any other?
You might think it is a strategic, Stuxnet on steroids-style cyber attack designed by a rival nation with deep pockets and lots of engineers to cripple American industry. While state-sponsored attacks remain a big threat to large corporations and the U.S. government, the cyber tools available to average hackers are increasing in potency at an alarming rate. The proliferation of tools allowing anyone to easily detect where a device connects to the Internet, combined with growing ability of private hackers to discover previously unknown vulnerabilities inherent in computer systems (called zero day exploits), now poses a large threat, according to Eric Rosenbach, deputy assistant secretary of defense for cyber policy.”
Source: The cyber threats keeping DoD officials awake right now | Killer Apps