5. Vulnerabilities of industrial systems

5.1 ICS specificities

Industrial control systems interact with physical systems, which creates special constraints. Firstly, as the computer system controls a physical system, it is not possible to abruptly stop the execution of a program without taking into account the state of the manufacturing process or the equipment. The latter must first be returned to a safe state. If, for example, a reaction is in progress, it may be necessary to cool down the system for a certain period of time before the system can be shut down. Secondly, since a software or configuration error can irreversibly degrade the physical system, the tendency is to observe the utmost caution when making updates or changes, or installing protective software that may slow down the system at a critical moment....