Risk Analysis in Fieldbus Networks Using the Example of KNX

Building automation is increasingly used to minimize energy consumption and increasing comfort and flexibility in buildings. When the KNX Association was founded in 1999 the need for security was quite low. Systems were usually not connected to the internet and so the standard lacks of nowadays common security requirements. To get an idea where the most serious problems are located in installations we present in this paper a method to calculate a risk for the different network segments. Without limiting the generality KNX is used as one example of fieldbuses. The basic concepts in the communication of fieldbus devices are present in KNX and the results can easily be transferred to other fieldbus protocols.