Updated

Senior officials from the Department of Justice and the FBI on Thursday said three Iranians had been indicted on cyber-related charges after a ransom scheme hit critical U.S. infrastructure.

The Iranian culprits  were named as Mansour Ahmadi, 34, Ahmad Khatibi Aghda, 45, and Amir Hossein Nickaein Ravari, 30, are believed to still be residing in Iran.

There is a $10 million reward for information relating to the three individuals. 

The hackers are not believed to have been acting on behalf of the Iranian government, but have connections to the Iranian Revolutionary Guard – which is deemed a terrorist organization by the U.S.

Senior DOJ and FBI officials told reporters Wednesday this attack was a "side job" purely for profit and acted "with impunity."

Iran cyber

Illustration set of flags made from binary code targets. (iStock)

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"Hundreds" were targeted in the attack including local governments, state governments, transportation companies, aerospace, power utility companies and even a domestic violence shelter, according to DOJ officials. 

"Ransom-related cyberattacks — like what happened here — are a particularly destructive form of cybercrime," U.S. Attorney Sellinger said. "No form of cyber-attack is acceptable, but ransomware attacks that target critical infrastructure services, such as health care facilities and government agencies, are a threat to our national security."

The hacking suspects targeted "known vulnerabilities" the victim's systems, not only in the U.S. but in other countries, by encrypting and stealing data from their networks, threatening to release the stolen information if exuberant sums were not dolled out.

Entities in the U.K., Israel, Iran, and elsewhere, were targeted in the attacks that caused "damage and losses to the victims."

Hacker attacking internet

Hacker attacking internet (iStock)

"These defendants may have been hacking and extorting victims – including critical infrastructure providers – for their personal gain, but the charges reflect how criminals can flourish in the safe haven that the Government of Iran has created and is responsible for," Assistant Attorney General Matthew Olsen said. "According to the Indictment, even other Iranians are less safe because their own government fails to follow international norms and stop Iranian cyber criminals.".

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Some of the victims did end up paying the hackers, the department said. 

Officials did not clarify the extent of the cyber-attacks or specify if power was cut as a result of attack.

The investigation remains ongoing.