SMS spam: A holistic view

Spam has been infesting our emails and Web experience for decades; distributing phishing scams, adult/dating scams, rogue security software, ransomware, money laundering and banking scams... the list goes on. Fortunately, in the last few years, user awareness has increased and email spam filters have become more effective, catching over 99% of spam. The downside is that spammers are constantly changing their techniques as well as looking for new target platforms and means of delivery, and as the world is going mobile so too are the spammers. Indeed, mobile messaging spam has become a real problem and is steadily increasing year-over-year. We have been analyzing SMS spam data from a large US carrier for over six months, and we have observed all these threats, and more, indiscriminately targeting large numbers of subscribers. In this paper, we touch on such questions as what is driving SMS spam, how do the spammers operate, what are their activity patterns and how have they evolved over time. We also discuss what types of challenges SMS spam has created in terms of filtering, as well as security.