“In short, a likely inexperienced intruder somehow learned the credentials needed to remotely access Oldsmar’s water system, did little to hide his activity, and then tried to change settings by such a wide margin that the alterations would be hard to overlook.”
The intruder got in through TeamViewer and raised the lye level 100 times. A supervisor happened to be watching the screen. That is the good outcome. Researchers post exposed control panels for water and power plants all the time. A quiet attacker would have left no trace, and the town would never have known.