Verizon breach digest reports a number of cyber attacks including one against an unnamed water utility, described in the document as the Kemuri Water Company (KWC) The operator behind the water utility hired Verizon to assess its systems, during the investigation the experts discovered evidence. The entire control infrastructure was relying on an IBM AS/400 system, a system dated 1988, that was used by the operator to control every OT device in the facility. Many critical IT and OT functions ran on a single AS400 system. This system functioned as a router with direct connections into several networks.”]
Source: https://securityaffairs.co/wordpress/45550/hacking/cyber-attacks-waterr-utility.html