Abstract:
There is a great concern about the potential for people to leak private information on social
networks. There are many anecdotal examples of this, but few quantitative studies. This
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 sharing
behaviour on OSNs either via pro le 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, pre xed 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. Fewer females users shared mobile numbers on Online Social Networks. Users utilized
other social networking platforms and third party applications like Twitterfeed and TweetDeck,
to post mobile numbers on multiple OSNs. In contradiction to the user's perception of numbers
spreading quickly on OSN, we observed that except for emergency, most numbers did not di use
deep.
To assess risks associated with mobile numbers exposed on OSNs, we used numbers to gain
sensitive information about their owners (e.g. name, Voter ID) by collating publicly available
data from OSNs, Truecaller, Open government data repository (OCEAN). On using the numbers
on WhatApp, we obtained a myriad of sensitive details (relationship status, BBM pins, travel
plans) of the mobile number owner. We communicated the observed risks to the owners by calling
them on their mobile number. Few users were surprised to know about the online presence of
their number, while few users intentionally posted it online for business purposes. 1 We observed
that 38.3% of users who were unaware of the online presence of their number have posted their
number themselves on the social network. With these observations, we highlight that there is
a need to monitor leakage of mobile numbers via pro le and public posts. To the best of our
knowledge, this is the rst exploratory study to critically investigate the exposure of Indian
mobile numbers on OSNs.
