Hackers take over city water purification system

Change the settings on how the water is treated:

A group of hackers, previously involved in various hacktivism campaigns, have accidentally made their way into an ICS/SCADA system installed at a water treatment facility and have altered crucial settings that controlled the amount of chemicals used to treat tap water.

This strange hacking incident is described in Verizon's 2016 Data Breach Digest (page 38, Scenario 8), a collection of case studies that the company's RISK team was brought in to investigate.

The victim of the hack is a company that Verizon identified under the generic name of Kemuri Water Company (KWC). As the RISK team explains, the company noticed that, for a couple of weeks, its water treatment center was behaving erratically, with chemical values being modified out of the blue.

Suspecting something was wrong - and something that its IT staff wasn't able to spot - the company brought in Verizon's RISK team to investigate.

KWC was exposing its internal network to the Internet

Good idea, Scooter.  Stalin would have had you shot.