Collaborative Spam Filtering Using E-Mail Networks

Widespread Internet use has led to the emergence of several kinds of large-scale social networks in cyberspace, most notably e-mail networks. Unfortunately, the tremendous convenience that e-mail affords comes at a high price: Although the network's underlying connectivity is hidden, making it almost impossible to build a comprehensive directory of every individual's contact lists, e-mail addresses themselves can be easily obtained from publicly available documents. Spammers have exploited this vulnerability to inundate users with unsolicited bulk e-mail. A distributed spam-filtering system that leverages e-mail networks' topological properties is more efficient and scalable than client-server-based solutions. Large-scale simulations of a prototype system reveal that this approach achieves a near-perfect spam-detection rate while minimizing bandwidth cost