1.2 Basics of SPIN

SPIN system

To address the two threats mentioned in the previous paragraph, we developed the SPIN (Security and Privacy for In-home Networks) system.

SPIN introduces the concept of a reverse firewall, with which the internet can be protected against DDoS attacks from IoT devices. Suspicious traffic from IoT devices that exhibit abnormal behavior can be blocked. Similarly, SPIN also protects users against, for example, the leakage of privacy-sensitive information by IoT devices to services on the internet.

SPIN also visualises traffic flows so that the user can see what is happening on the network.

We released the SPIN software as open source based on OpenWRT, so that anyone with the proper set of skills can compile and install it. We also publish our results so the community can benefit from our experiences.

Overview and components


The figure above (click to enlarge) is a global overview of the architecture of a SPIN-based system, featuring two distinct component groups: lightweight SPIN agents that measure network traffic and more intelligent controllers. The separation is new and enables us to use the system for a larger set of deployment scenarios.

An agent captures traffic flows, generates flow digests, and can block traffic flows. A controller receives digests from one or more agents, analyses them, and can order the agents to block the traffic flows from certain IoT devices. For example, a controller may detect that a device is generating traffic flows that match the Mirai botnet. The controller then orders the appropriate agent to quarantine (block) the infected device.

Controllers and agents may be hosted on the same device, but our new design also supports deployment scenarios with several agents and one or a few controllers elsewhere in the network. For example, there may be a separate Wi-Fi hotspot on each floor of a house, each with its own agent and all governed by a central controller that runs on a general-purpose, always-on device such as a network-attached storage (NAS) device.

The SPIN platform can be extended with application components that can be implemented by (commercial) organisations, the SPIN community, or by the research community.

A well-defined API provides application developers with necessary of the home network and its IoT devices so developers don’t have to deal with the particularities of low-level measurements.