Attack vulnerability of peer-to-peer networks and cost-effective immunization

Currently, great efforts on network security are being made to concern software protection and prevention of loopholes, rather than the network topology. In this paper, we present a detailed and in-depth study on the response of peer-to-peer (P2P) networks subject to attacks, and investigate how to improve their attack survivability with a viewpoint of topological properties. We first, by extensive simulations, examine the attack vulnerability of P2P networks and find that these networks are extremely robust to random attacks whereas highly vulnerable under intentional targeted attacks. Based on these findings, we then develop a novel framework better characterizing the immunization of Gnutella-like P2P networks by taking into account the cost of curing infected peers. Finally, we propose a unique defense policy against intentional attacks and verify its performance merits via comprehensive experiments.