We are going to take the assessment approach, explained in the previous section and explore some details by applying it step by step to a fictive system under consideration. Let's imagine that the Slumbertown Mill from the previous chapter decided to hire a security consultant to help them assess and address risk to their ICS network. After outlining contractual details such as scope, timelines and deliverables, a security consultant will typically plan a site visit to start gathering information needed to complete the assessment.
The onsite security consultant will normally start with consulting existing documentation such as IP and asset lists, software and hardware inventory documentation and tracking systems in order to compile a list of assets and their IP addresses. The task is to find all of the assets of the system under consideration.
On a regular IT network, discovery of assets is often accomplished...