The comments by Mark Weatherford, deputy undersecretary for cybersecurity, come as a handful of American banks are dealing with a fourth week of DDoS (distributed denial-of-service) attacks on their websites.

DDoS attacks are one of the simplest forms of cyberattack and seek to push websites offline by overloading them with junk traffic so they cannot handle legitimate requests from users.

The attacks have hit banks including Wells Fargo, U.S. Bancorp, PNC Financial Services Group, Citigroup, Bank of America and JPMorgan Chase, and have been claimed by hackers in Iran.

"This has been an eye-opening experience for a lot of very, very large organizations," Weatherford said. "It's got a lot of people's attention. Not just the banks, but the ISPs and some of the other third-party providers as well."

Weatherford was speaking at a cybersecurity awareness conference in Santa Clara, California, that was organized by the Bay Area Council, a public policy advocacy group made up of local companies.