Malware

Another University, which used a similar approach with dedicated sensors to monitor their campus, is suddenly attacked by a Ransomware Worm, which encrypts all the data on the sensors and ask for the University to pay a ransom in Bitcoin, threatening to “brick” the sensors.
The University is worried something similar might happen to the network of sensors described in the previous Case Studies.
Describe a method to analyse the risk of a ransomware attack.