gore: Routing-Assisted Defense Against DDoS Attacks

Abstract

We present gore, a routing-assisted defense architecture against distributed denial of service (DDoS) attacks that provides guaranteed levels of access to a network under attack. Our approach uses routing to redirect all traffic destined to a customer under attack to strategically-located gore proxies, where servers filter out attack traffic and forward authorized traffic toward its intended destination.

Our architecture can be deployed incrementally by individual ISPs, does not require any collaboration between ISPs, and requires no modifications to either server- or client- software. Clients can be authorized through a web interface that screens legitimate users from outsiders or automated zombies. Authenticated clients are granted limited-time access to the network under attack. The gore architecture allows ISPs to offer DDoS defenses as a value-added service, providing necessary incentives for the deployment of such defenses. We constructed a PC-based testbed to evaluate the performance and scalability of gore. Our preliminary results show that gore is a viable approach, as its impact on the filtered traffic is minimal, in terms of both end-to-end latency and effective throughput. Furthermore, gore can easily be scaled up as needed to support larger numbers of clients and customers using inexpensive commodity PCs.