Admiral Michael Rogers, director of the National Security Agency and US cyber commander outlined three things that concern him the most when thinking about cyber-threats to the United States:

1. Cyber attacks that do infrastructure damage
2. Data manipulation
3. Non-state actors

https://www.yahoo.com/tech/nsa-chief-3-cyber-threats-140911247.html?soc_src=social-sh&soc_trk=tw