Malicious Cyber Actors Targeting Water and Wastewater Sector Internet- Facing Programmable Logic Controllers, Causing Operational Disruptions

The Federal Bureau of Investigation (FBI) and Environmental Protection Agency (EPA) are issuing this Public Service Announcement (PSA) to warn critical infrastructure asset owners and operators that malicious cyber actors (MCAs) are conducting cyber attacks targeting Operational Technology (OT) devices, including Rockwell Automation/Allen-Bradley Programmable Logic Controllers (PLCs), specifically MicroLogix 1100 and 1400 series. Since 27 July 2026, Water and Wastewater Sector (WWS) utility companies in at least seven states have reported incidents to the FBI, and some of that activity degraded water operations. While the FBI has only observed this behavior with the referenced Rockwell PLCs, similar considerations should also be made with other branded PLCs.