The FBI Cyber Division warned organizations and companies that Iran-affiliated hackers are targeting U.S. critical infrastructures.
The warning comes hours before the 8 PM ET deadline President Donald Trump gave Iran to open the Strait of Hormuz.
“Iran-affiliated cyber actors are targeting operational technology devices across US critical infrastructure, including programmable logic controllers (PLCs),” the division wrote on X. “These attacks have led to diminished PLC functionality, manipulation of display data and, in some cases, operational disruption and financial loss.”
A PLC is a heavy-duty computer:
At its core, a PLC is a rugged digital computer specifically designed for industrial applications. Unlike standard computers, PLCs are built to withstand harsh environments, including extreme temperatures, humidity and electrical interference. They play a huge role in automating various processes, from manufacturing operations to complex machinery.Picture this—a PLC is like the brain of a robot or a machine, managing all the actions without human intervention. It monitors input devices, makes decisions based on pre-programmed conditions and controls output devices.
“Since at least March 2026, the authoring agencies identified (through engagements with victim organizations) an Iranian-affiliated APT group that disrupted the function of PLCs,” the FBI wrote in its advisory. “These PLCs were deployed across multiple U.S. critical infrastructure sectors (including Government Services and Facilities, WWS, and Energy sectors) within a wide variety of industrial automation processes.”
The FBI said the hackers use overseas-based IP addresses on “leased third-party hosted infrastructure with configuration software.”
The advisory noted that hackers had accessed PLCs made by Rockwell Automation/Allen-Bradley and recommended disconnecting them from remote access and reconnecting them securely.
The FBI also wants the companies and organizations to back up everything offline.
Iran cyber actors have stepped up their game since Operation Epic Fury began at the end of February.
The hackers targeted FBI Director Kash Patel in late March, leaking emails and photos online.
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