On the security of security extensions for IP-based KNX networks

The traditional areas of building automation like heating, ventilation and air conditioning as well as lighting and shading are more and more extended by services requiring a more robust security infrastructure like alarm-and access control systems. Additionally, building automation networks get integrated into existing IP-based networks, or even communicate directly over the Internet. Therefore, the attack surface of building automation systems has increased dramatically. This requires a solid security architecture and a profound knowledge of possible attack vectors. This work reviews two security extensions for KNXnet/IP regarding their individual security properties. Thereby, it is pointed out that the current version of the draft specification, called KNXnet/IP Secure, lacks some relevant details and has certain limitations concerning the provided level of security.