  Internet of Things (IoT) is becoming an increasingly attractive target for
cybercriminals. We observe that many attacks to IoTs are launched in a
collusive way, such as brute-force hacking usernames and passwords, to target
at a particular victim. However, most of the time our defending mechanisms to
such kind of attacks are carried out individually and independently, which
leads to ineffective and weak defense. To this end, we propose to leverage
Software Defined Networks (SDN) to enable cooperative security for legacy
IP-based IoT devices. SDN decouples control plane and data plane, and can help
bridge the knowledge divided between the application and network layers. In
this paper, we discuss the IoT security problems and challenges, and present an
SDN-based architecture to enable IoT security in a cooperative manner.
Furthermore, we implemented a platform that can quickly share the attacking
information with peer controllers and block the attacks. We carried out our
experiments in both virtual and physical SDN environments with OpenFlow
switches. Our evaluation results show that both environments can scale well to
handle attacks, but hardware implementation is much more efficient than a
virtual one.
