An unintended consequence of the global deployment of IoT devices is that they provide a fertile breeding ground for IoT botnets. An adversary can take advantage of an IoT botnet to launch DDoS attacks against telecommunication services. Due to the magnitude of such an attack, legacy security systems are not able to provide adequate protection. The impact ranges from loss of revenue for businesses to endangering public safety.
This risk has prompted academia, government, and industry to reevaluate the existing de- fence model. The current model relies on point solutions and the assumption that adversaries and their attacks are readily identifiable. But adversaries have challenged this assumption, building a botnet from thousands of hijacked IoT devices to launch DDoS attacks. With bot- net DDoS attacks there are no clear boundary where the attacks originate and what defensive measures to use.
The research question is: in what ways programmable networks could defend against Session Initiation Protocol (SIP) Distributed Denial-of-Service (DDoS) flooding attacks from IoT botnets? My significant and original contribution to the knowledge is a scalable and collaborative defence framework that secures the edges of IoT networks with Virtual Network Function (VNF), Software-Defined Networking (SDN), and Blockchain technology to prevent, detect, and mitigate SIP DDoS flooding attacks from IoT botnets.
Successful experiments were performed using VNF, SDN, and Blockchain. Three kinds of SIP attacks (scan, brute force, and DDoS) were launched against a VNF running on a virtual switch and each was successfully detected and mitigated. The SDN controller gathers threat intelligence from the switch where the attacks originate and installs them as packet filtering rules on all switches in the organisation. With the switches synchronised, the same botnet outbreak is prevented from attacking other parts of the organisation. A distributed application scales this framework further by writing the threat intelligence to a smart contract on the Ethereum Blockchain so that it is available for external organisations. The receiving organisation retrieves the threat intelligence from the smart contract and installs them as packet filtering rules on their switches. In this collaborative framework, attack detection/mitigation efforts by one organisation can be leveraged as attack prevention efforts by other organisations in the community
