An attacker broke into the Florida city of Oldsmar's water treatment system on Feb. 5 and temporarily set the amount of lye applied to drinking water to toxic levels before an operator discovered the breach and corrected the settings.
Local officials from Oldsmar and Pinellas County, Fla., said in a press briefing today that the water supply itself was not affected and the public was "never in danger." The attacker was able to remotely access the system for up to five minutes and raise the level of sodium hydroxide (aka lye) by a factor of more than 100, according to Pinellas County Sheriff Bob Gualtieri. At that point the operator noticed the anamoly and reset the proper levels of lye, which is used for controlling water acidity levels.
The officials said systemic redundancies would have triggered alarms had the malicious settings not been detected.
"The protocols that we have in place, monitoring protocols, they work; that's the good news," said Oldsmar Mayor Eric Seidel. "Even had they not caught them, there's redundancies in the system that would have caught the change in the pH level."
The remote access function - which Reuters reports was TeamViewer - has been disabled on the water treatment computer system. The FBI, US Secret Service, and local officials are investigating the attack.