Cybersecurity for Industrial Control Systems

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rIsk AssessMent teChnIques

In other words, ICS risk assessors do not know what they do not

know about ICS and should therefore calculate risk backwards from

an ideal state by assessing how far a target of evaluation is from this

state. At the very least, this will provide a minimum reading of risk,

since it does not start with the premise that the most likely threats

can be enumerated. Instead, the ideal-based system, they say, creates

the ideal ICS security architecture, including the dened metrics, and

then assesses against how much of the ideal is reected in the current

system and perhaps in future planned improvements.

As a fresh approach, the ideal-based system certainly possesses

merit, but it also immediately leads to complex ...