Call me maybe: understanding nature and risks of sharing mobile numbers on online social networks

Abstract

Little research explores the activity of sharing mobile numbers on OSNs, in particular via public posts. In this work, we understand the characteristics and risks of mobile numbers shared on OSNs either via profile or public posts and focus on Indian mobile numbers. We collected 76,347 unique mobile numbers posted by 85,905 users on Twitter and Facebook and analyzed 2,997 numbers, prefixed with +91. We observed that most users shared their own mobile numbers to spread urgent information and to market products, IT facilities and escort business. Users resorted to applications like Twitterfeed and TweetDeck to post and popularize mobile numbers on multiple OSNs. To assess risks associated with mobile numbers exposed on OSNs, we used mobile numbers to gain sensitive information (e.g. name, Voter ID) about their owners. We communicated the observed risks to the owners by calling them on their mobile number. Few users were surprised to know the online presence of their number, while few users intentionally put it online for business purposes. With these observations, we highlight that there is a need to monitor leakage of mobile numbers via profile and public posts. To the best of our knowledge, this is the first exploratory study to critically investigate the exposure of mobile numbers on OSNs.