RepHi: A novel attack against P2P reputation systems

Reputation systems are having increasing influence on guarding P2P networks. However, reputation systems themselves are vulnerable to attack. Due to the nature of aggregating ratings, the reputation scores of certain peers can be manipulated intentionally by adversaries. In this paper, we report the discovery of a novel attack, named RepHi (Reputation Hijack), against rating-based reputation systems, such as those used in P2P networks. In RepHi, attackers disguise as routers to hijack and modify ratings. This attack can cause multi-dimensional damage, that is, undermining reputation systems, manipulating reputation and hurting the credibility of raters. We conduct an investigation on RepHi, including basic ideas and case studies. Compared with other known attacks, the RepHi attackers require less efforts to achieve the similar goals.