Throttling DDoS Attacks

Distributed Denial of Service poses a significant threat to the Internet today. In these attacks, an attacker runs a malicious process in compromised systems under his control and generates enormous number of requests, which in turn can easily exhaust the computing resources of a victim web server within a short period of time. Many mechanisms have been proposed till date to combat this attack. In this paper we propose a new solution to reduce the impact of a distributed denial of service attack on a web server by throttling the client's CPU. The concept of source throttling is used to make the client pay a resource stamp fee, which is negligible when the client is making a limited number of requests but becomes a limiting restriction when he is making a large number of requests. The proposed solution makes use of the integer factorization problem to generate the CPU stamps. We have packaged our solution as an API so that existing web applications can easily deploy our solution in a layer that is transparent to the underlying application.