Cyber attacks on the biggest U.S. banks, including JPMorgan Chase & Co. and Wells Fargo & Co., have breached some of the nation’s most advanced computer defenses and exposed the vulnerability of its infrastructure, said cybersecurity specialists tracking the assaults.
The attack, which a U.S. official yesterday said was waged by a still-unidentified group outside the country, flooded bank websites with traffic, rendering them unavailable to consumers and disrupting transactions for hours at a time.