The U.S government warned industrial firms this week about a hacking campaign targeting the nuclear and energy sectors, the latest event to highlight the power industry’s vulnerability to cyber attacks.
Since at least May, hackers used tainted “phishing” emails to “harvest credentials” so they could gain access to networks of their targets, according to a joint report from the U.S. Department of Homeland Security and Federal Bureau of Investigation.
The report provided to the industrial firms was reviewed by Reuters on Friday. While disclosing attacks, and warning that in some cases hackers succeeded in compromising the networks of their targets, it did not identify any specific victims.
“Historically, cyber actors have strategically targeted the energy sector with various goals ranging from cyber espionage to the ability to disrupt energy systems in the event of a hostile conflict,” the report said.
Homeland Security and FBI officials could not be reached for comment on the report, which was dated June 28.
The report was released during a week of heavy hacking activity.
A virus dubbed “NotPetya” attacked on Tuesday, spreading from initial infections in Ukraine to businesses around the globe. It encrypted data on infected machines, rendering them inoperable and disrupting activity at ports, law firms and factories.
On Tuesday the energy-industry news site E&E News reported that U.S. investigators were looking into cyber intrusions this year at multiple nuclear power generators.
Reuters has not confirmed details of the E&E News report, which said there was no evidence safety systems had been compromised at affected plants.
The activity described in the U.S. government report comes at a time when industrial firms are particularly anxious about threat that hackers pose to their operations.
Industrial firms, including power providers and other utilities, have been particularly worried about the potential for destructive cyber attacks since December 2016, when hackers cut electricity in Ukraine.
U.S. nuclear power generators PSEG (PEG.N), SCANA Corp (SCG.N) and Entergy Corp (ETR.N) said they were not impacted by the recent cyber attacks. SCANA’s V.C. Summer nuclear plant in South Carolina shut down on Thursday due to a problem with a valve in the non-nuclear portion of the plant, a spokesman said.
Another nuclear power generator, Dominion Energy (D.N), said it does not comment on cyber security.
Two cyber security firms said on June 12 that they had identified the malicious software used in the Ukraine attack, which they dubbed Industroyer, warning that it could be easily modified to attack utilities in the United States and Europe.