WASHINGTON • Seven Iranian hackers carried out a coordinated cyber attack on dozens of American banks, causing millions in lost business, and tried to shut down a New York dam, the United States government said in an indictment that for the first time accused individuals tied to another country of trying to disrupt critical infrastructure.
It said the seven accused were believed to have been working on behalf of Iran's government and the Islamic Revolutionary Guard. Those named live in Iran, and the Iranian government is not expected to extradite them. There was no immediate comment from Teheran.
At least 46 major financial institutions and financial sector firms were targeted, including JPMorgan Chase and American Express, Thursday's indictment said. AT&T also was targeted.
The hackers allegedly made distributed-denial-of-service attacks on the banks - knocking networks offline by overwhelming them with spammed traffic.
"These attacks were relentless, they were systematic, and they were widespread," US Attorney-General Loretta Lynch told a Washington news conference.
The indictment from a federal grand jury in New York said the hits occurred from 2011 to 2013. Washington previously accused Chinese military officers and the North Korean government of cyber attacks on US businesses.
The attack on the Bowman Avenue Dam in Rye Brook was especially alarming, Ms Lynch said, because it marked one of the first known intrusions on critical infrastructure. A stroke of good fortune stopped the hackers from gaining operational control of the flood gates because the dam had been manually disconnected for routine maintenance, she said.
The dam hack was a "game-changing event" that prompted investigators to uncover other systems vulnerable to similar attacks, said Mr Andre McGregor, a lead case investigator in the dam intrusion.
"The investigation's discovery of many more exposed computer systems with vulnerable management consoles is a constant reminder that basic cyber hygiene remains at the forefront of the battle against cyber attacks," said Mr McGregor, now director of security at Silicon Valley cyber security firm Tanium.
The defendants were identified as Ahmad Fathi, Hamid Firoozi, Amin Shokohi, Sadegh Ahmadzadegan, Omid Ghaffarinia, Sina Keissar and Nader Seidi, all citizens and residents of Iran.
The indictments are Washington's latest attempt to more publicly confront cyber attacks by other countries against the US.
The campaign began two years ago when the Justice Department accused five members of China's People's Liberation Army of hacking several Pennsylvania-based companies in an alleged effort to steal trade secrets. It continued with President Barack Obama's vow to "respond proportionally" against North Korea for the destructive hack against Sony Pictures.