Exploiting the Security Weaknesses of the Gnutella Protocol

Peer-to-Peer (P2P) file-sharing systems such as Gnutella, Morpheus and Freenet have recently attracted a lot of interest from the internet community because they realized a distributed infrastructure for sharing files. Such systems have shifted the Web’s Client-Server model paradigm into a Client-Client model. The tremendous success of such systems has proven that purely distributed search systems are feasible and that they may change the way we interact on the Internet. Beside the several advantages that have been uncovered by P2P systems, such as robustness, scalability and high fault tolerance various other questions and issues arise in the context of Security. Many P2P protocols are bundled along with an adequate amount of security mechanisms but are proprietary which makes their analysis difficult. The Gnutella Protocol on the other hand is an open protocol, which doesn’t highlight security in the sake of its simplicity. Most security weaknesses of the Gnutella Protocol could be avoided if the protocol was taking into account that Peers may misbehave. In this paper we provide an overview of the Gnutella Protocol Specification, describe several of its weaknesses and show how they can be turned into Distributed Denial of Service Attacks, User’s Privacy Violation and IP Harvesting. We present the weaknesses with experimental attacks that we have performed on the Gnutella Network. We finally evaluate how these attacks could be avoided and suggest in some cases improvements on the protocol.