Is Email Business Dying?: A Study on Evolution of Email Spam Over Fifteen Years

With the increasing dedication and sophistication of spammers, email spam is a persistent problem even today. Popular social network sites such as Facebook, Twitter, and Google+ are not exempt from email spam as they all interface with email systems. While some report predicts that email spam business is dying due to the decreasing volume of email spam. Whether email spam business is really dying is an interesting question. In this paper, we analyze email spam trends on Spam Archive dataset, which contains 5.5 million spam emails over 15 years (1998 – 2013). We statistically analyze emails contents including header information (e.g. content type) and embedded items (e.g. URL links). Also, we investigate topic drift using topic modeling technique. Moreover, we perform network analysis on sender-to-receiver IP routing networks. Our study shows the dynamic nature of email spam over one and a half decades and demonstrate that the email spam business is not dying but more capricious.