The sophisticated denial-of-service cyber attacks have been underway for several months and involve Iranian-origin hackers who flood banking and financial institution web sites with massive log-in attempts that disrupt or halt remote banking services.

“The are going after the same types of sites,” said an intelligence official familiar with reports of the attacks.

The official criticized the Obama administration for failing to protect American corporations from what the official said were state-sponsored cyber attacks.

Critics in government and the private sector say the U.S. government remains unprepared to respond to such coordinated covert cyber attacks.