You Can SPIT, But You Can't Hide: Spammer Identification in Telephony Networks
SPam over Internet Telephony (SPIT) is a new form of spam delivered using the phone network. With the low cost of Internet telephony, SPIT has become an attractive alternative for spammers to carry out unsolicited marketing and phishing. SPIT is more intrusive than email spam as it demands immediate recipient attention. In this paper, the authors study characteristics of communications in a phone network with the objective of identifying "SPITters". They collect and analyze the data from one of the largest phone providers in North America. First, they propose a new technique, Loose Tie Detection (LTD), to identify outliers based on social ties. Second, they introduce Enhanced Progressive Multi Grey-Leveling (EPMG), which identifies outliers based on call density and reciprocity.