For more information on SCADAs, their vulnerabilities and exploitations, please see the SCADA tag.
An example article showing American vulnerability to SCADA attacks:
Several attacks have already taken place against regional power plants in Ukraine, resulting in several short-term blackouts in December 2015. It was the first recorded case of power outages being caused by cyber attacks and originated from a type of malware known as BlackEnergy.
It is not clear who was behind the attacks but a military spokesperson stated last week that they were originating from Russia. Another type of malware has since been discovered by investigators looking into the December cyber attacks, although researchers say it is impossible to know how many systems are currently at risk. Continue reading