Investigators are probing whether Iranian hackers are behind this week's malicious cyber activity against water systems in Minnesota. If they are found to be the culprits, it would not be the first time.

More than 30 facilities disrupted in 'coordinated cyberattack,' though officials have yet to name a culprit

While it is not yet clear who is responsible for the attacks, Iranian-linked hackers have, for years, targeted U.S. water systems to varying levels of success...