CISA Says Hackers Targeted Over 100 U.S. Water Systems in July

CISA said it observed cyberattacks targeting more than 100 internet-exposed systems across the U.S. water and wastewater sector. The figure adds new context to attacks affecting water providers in Michigan, Minnesota, and at least five other states. The warning comes amid suspected Iran-backed cyberattacks targeting critical water systems across the United States.

The attacks have largely targeted programmable logic controllers, or PLCs, which are used to control physical systems and machinery across water providers, energy systems, and other critical infrastructure. TechCrunch reports that recent activity has involved PLCs made by several manufacturers, including Rockwell, Schneider Electric, and Siemens. CISA previously said some attacks relied in part on AI tools using public information to develop scripts capable of targeting vulnerable Siemens PLCs.

The intrusions have had little effect on water or wastewater supplies to local communities, according to the report. Still, they have caused outages and operational disruption while incident responders investigate the breaches. CISA previously reported that some intrusions let hackers modify affected PLCs to disable shutdown processes and alarms, potentially creating unsafe conditions without notifying operators.

Many affected communities are rural or isolated, where disruption to critical infrastructure can affect a large area of people. Reports cited by TechCrunch say U.S. intelligence believes Iran is likely behind the largely opportunistic attacks, though officials have not made a concrete attribution. The incidents are fueling wider concern about the cybersecurity and resilience of U.S. critical infrastructure.