Once primarily an information network, the Internet is evolving into a creature with eyes, ears and arms as sensors and actuators are added. Common security threats haunting our information systems today will inevitably migrate to networked systems controlling physical processes. German computer scientists explored the risk of automated buildings and even entire smart cities falling prey to a botnet.

In their paper Envisioning Smart Building Botnets computer scientists Steffen Wendzel, Viviane Zwanger, Michael Meier and Sebastian Szlósarczyk, all part of the Cyber Defense Research Group of Fraunhofer institute in Bonn, combine research into botnets, building automation systems and covert channel attacks to assess the potential of smart building botnets.

Botnets
In common information systems a botnet or robot network consists of machines that run bot software which enables a single point of control over the nodes in the network. There are benevolent use cases but botnets are best known for their illegal variety: when systems are assimilated without their users' knowledge. The botherder can command the zombie computers to send spam, divulge information about their legitimate user, or make them unwitting participants in DDoS attacks.

Building automation systems
If building automation systems (BAS) are compromised the number of possible abuses increase. Information retrieval is still on the table only now it also includes behavioral patterns of the building's occupants. But the true novelty lies in taking control of the physical capabilities of the system like controlling automated doors and windows, lighting and climate control systems, fire alarms and so on.

Smart building botnets
Should a number of compromised BAS be assimilated into a botnet then the adversary can significantly amplify the effects of an attack. Wendzel and his colleagues write that in the case of a botnet “new scenarios arise, namely the attack of larger infrastructure distributed over many buildings, smart cities, or, theoretically, even economies or states”. Possible scenario's they describe are for instance shutting down climate control in multiple server rooms to cause the servers to overheat and crash. Or the botnet could turn on all the electric devices under its control to cause peak electricity demand. Or a huge amount of people being locked in or locked out from their buildings.

These are but a few of the possibilities of what one could do with command and control over a large number of so called smart environments. It is safe to conclude that a smart building botnet could create tremendous havoc.

Low barrier
Wendzel and his team point out that no bot software exists for smart buildings yet. However, given the wealth of opportunities it holds it is likely only a matter of time before the black hat community will try its hand at it. And, the authors warn, though there are still barriers that need to be overcome, these aren't very high.

Covert channels
One of these barriers is hiding the command and control communication of the botnet. Because of the specific nature of BAS which is “highly deterministic, predictable, simplistic
and conservative”, according to Wendzel & co, it is “easy to detect anomalies” in the information flow. The scientists then substantiate their claim that this is not that big a hurdle by pointing out that the botnet communication can be hidden by existing covert channel techniques. A covert channel is a communication channel that wasn't intended in the system's design but nevertheless offers a route for data transfer. Such channels can be used to stealthily transfer information even if it “violates the system's security policy”.

Slack security
By pointing out the enormous harm smart building botnets can cause and the relative ease with which they can be created, Wendzel and his team hope to raise awareness for the insufficient attention given to security in smart environments.

Image: http://p2pbotnetracker.net/TrackingUI/