Critical infrastructure provides the essential services that underpin society and serve as the backbone of nation's economy, security, and health. There are 16 critical infrastructure sectors (according to US Homeland Security) whose assets, systems, and networks, whether physical or virtual, are considered so vital that their incapacitation or destruction would have a debilitating effect on security, national economic security, national public health or safety.

Because of information technologies being part of all of these sectors and communication being vital for many of them, it is vulnerable to cybernetic attacks.

High

http://www3.weforum.org/docs/GRR17_Report_web.pdf

https://www.dhs.gov/critical-infrastructure-sectors