FBI warns of cyberattacks targeting US water systems after incidents in Minnesota

The FBI and Environmental Protection Agency (EPA) warned Thursday that "malicious cyber actors" are targeting internet-facing operational technology used by US water and wastewater utilities after a series of cyberattacks disrupted facilities in at least seven states.

In a joint public service announcement, the agencies said attackers have targeted Rockwell Automation/Allen-Bradley programmable logic controllers (PLCs), remotely changing IP addresses and passwords, resulting in the loss of monitoring and control functions.

The reported operational effects include pressure loss and flooding, according to the statement.

The FBI and EPA urged operators to disconnect PLCs from direct internet exposure, strengthen authentication measures, "strictly control" network access and maintain the ability to operate systems manually in the event of cyber incidents.

The warning follows a coordinated cyberattack earlier this week that affected more than 30 community water systems in the midwestern US state of Minnesota.

According to media reports, US officials believe the campaign was likely carried out by Iranian hackers, though investigators have not reached a definitive conclusion and are also examining whether the attackers could have sought to disguise their identity.