The Price of Free: Privacy Leakage in Personalized Mobile In-App Ads Wei Meng, Ren Ding, Simon P. Chung, Steven Han, and Wenke Lee College of Computing Georgia Institute of Technology {wei, rding, pchung34, s.han}@gatech.edu,
[email protected] Abstract—In-app advertising is an essential part of the ecosys- always a concern. While ad personalization has been well tem of free mobile applications. On the surface, this creates a studied for web, relatively little research explores mobile ad win-win situation where app developers can profit from their personalization in terms of what user information is being work without charging the users. However, as in the case of collected. We believe research focused on mobile ad personal- web advertising, ad-networks behind in-app advertising employ ization is a significant pursuit for the following reasons: 1) personalization to improve the effectiveness/profitability of their Mobile devices are a lot more intimate to users; they are ad-placement. This need for serving personalized advertisements in turn motivates ad-networks to collect data about users and carried around at all times and are being used more and more profile them. As such, “free” apps are only free in monetary for sensitive operations like personal communications, dating, terms; they come with the price of potential privacy concerns. banking, etc. Therefore, privacy concerns regarding what infor- The question is, how much data are users giving away to pay for mation is collected for ad personalization are more serious. 2) “free apps”? Unlike in-browser advertising, where the advertisement content is strictly isolated from the rest of the displayed page by the In this paper, we study how much of the user’s interest and demographic information is known to these major ad networks well-known “same origin policy”, in-app advertising operates on the mobile platform.