ISIS has made no specific threats to US critical infrastructure, and no one knows for sure whether the militant group has any plans for a cyber attack against US interests. ICS/SCADA security experts dismiss dire predictions in some circles that ISIS — or any other group — could ultimately disrupt the US power grid via a distributed denial-of-service (DDoS) or other type of cyber attack. Real physical damage would require engineering expertise, such as understanding how the targeted centrifuges operate.”]
Source: https://www.darkreading.com/advanced-threats/isis-cyber-threat-to-us-under-debate