The skill required to carry out recent attacks on American banks has convinced United States government officials and security researchers that they are the work of Iran, The New York Times reported Wednesday, January 9. Since September, intruders have caused major disruptions to the online banking sites of Bank of America, Citigroup, Wells Fargo, U.S. Bancorp, PNC, Capital One, Fifth Third Bank, BB&T and HSBC. They employed DDoS attacks, or distributed denial of service attacks, named because hackers deny customers service by directing large volumes of traffic to a site until it collapses. No bank accounts were breached and no customers’ money was taken. Computer security experts say the attacks showed a level of sophistication far beyond that of amateur hackers. Also, the hackers chose to pursue disruption, not money: another earmark of state-sponsored attacks, the experts said.