Collective Spammer Detection in Evolving Multi-Relational Social Networks Shobeir Fakhraei James Foulds Madhusudana Shashanka ∗ y University of Maryland University of California Santa Cruz, CA, USA if(we) Inc. College Park, MD, USA San Francisco, CA, USA
[email protected] [email protected] [email protected] Lise Getoor University of California Santa Cruz, CA, USA
[email protected] ABSTRACT Keywords Detecting unsolicited content and the spammers who create Social Networks, Spam, Social Spam, Collective Classifica- it is a long-standing challenge that affects all of us on a daily tion, Graph Mining, Multi-relational Networks, Heteroge- basis. The recent growth of richly-structured social net- neous Networks, Sequence Mining, Tree-Augmented Naive works has provided new challenges and opportunities in the Bayes, k-grams, Hinge-loss Markov Random Fields (HL- spam detection landscape. Motivated by the Tagged.com1 MRFs), Probabilistic Soft Logic (PSL), Graphlab. social network, we develop methods to identify spammers in evolving multi-relational social networks. We model a so- cial network as a time-stamped multi-relational graph where 1. INTRODUCTION vertices represent users, and edges represent different ac- Unsolicited or inappropriate messages sent to a large num- tivities between them. To identify spammer accounts, our ber of recipients, known as \spam", can be used for various approach makes use of structural features, sequence mod- malicious purposes, including phishing and virus attacks, elling, and collective reasoning. We leverage relational se- marketing of objectionable materials and services, and com- quence information using k-gram features and probabilistic promising the reputation of a system. From printed ad- modelling with a mixture of Markov models.