Iranian hackers penetrated the industrial control system of a dam near New York City in 2013, raising concerns about the security of US critical infrastructure. The hackers used a machine that scanned the Internet for vulnerable US industrial control systems (ICS), but the strange circumstance is that threat actors appeared to be focusing on a specific range of internet addresses. The US has the highest number of ICS and SCADA systems exposed on the internet and many are easily identifiable with search engines like Shodan or Censys.”]
Source: https://securityaffairs.co/wordpress/42964/cyber-crime/iranian-hackers-penetrated-ny-dam.html