Securing the Software-Defined Network Control Layer
Download: Paper (PDF)
Date: 7 Feb 2015
Document Type: Briefing Papers
Additional Documents: Slides
Associated Event: NDSS Symposium 2015
Software-defined networks (SDNs) pose both an opportunity and challenge to the network security community. The opportunity lies in the ability of SDN applications to express intelligent and agile threat mitigation logic against hostile flows, without the need for specialized inline hardware. However, the SDN community lacks a secure control-layer to manage the interactions between the application layer and the switch infrastructure (the data plane). There are no available SDN controllers that provide the key security features, trust models, and policy mediation logic, necessary to deploy multiple SDN applications into a highly sensitive computing environment. We propose the design of security extensions at the control layer to provide the security management and arbitration of conflicting flow rules that arise when multiple applications are deployed within the same network. We present a prototype of our design as a Security Enhanced version of the widely used OpenFlow Floodlight Controller, which we call SE-Floodlight. SE-Floodlight extends Floodlight with a security-enforcement kernel (SEK) layer, whose functions are also directly applicable to other OpenFlow controllers. The SEK adds a unique set of secure application management features, including an authentication service, role-based authorization, a permission model for mediating all configuration change requests to the data-plane, inline flow-rule conflict resolution, and a security audit service. We demonstrate the robustness of our system implementation both through a comprehensive functionality testing and a performance evaluation that illustrates its sub-linear scaling properties.