text: In the last decade, the advertisement market spread significantly in the web and mobile app system. Its effectiveness is also due thanks to the possibility to target the advertisement on the specific interests of the actual user, other than on the content of the website hosting the advertisement. In this scenario, became of great value services that collect and hence can provide information about the browsing user, like Facebook and Google. In this paper, we show how to maliciously exploit the Google Targeted Advertising system to infer personal information in Google user profiles. In particular, the attack we consider is external from Google and relies on combining data from Google AdWords with other data collected from a website of the Google Display Network. We validate the effectiveness of our proposed attack, also discussing possible application scenarios. The result of our research shows a significant practical privacy issue behind such type of targeted advertising service, and call for further investigation and the design of more privacy-aware solutions, possibly without impeding the current business model involved in online advertisement.
  @cite_13: The main goal of this chapter is to present a state-of the-art of behavioural tracking on the Internet and to highlight some of the resulting potential privacy threats. This chapter is structured as follows: First section introduces the concept of behavioural tracking. The following sections describe how tracking is performed by web sites, location-based services and social networks, respectively. Final section presents some of the existing tracking-prevention solutions. Finally, the author concludes the report and proposes some recommendations.
summary: In literature, several works deal with behavioral targeting in Online Ad Systems, highlighting their potential privacy threats @cite_13 . The novelty of the current work is that it presents and maliciously exploits a feature of the Google advertising system, which allows a remote attacker to infer user personal information, as interests and navigation behavior. In the following we review the main research works related to privacy issues and online advertisement.