Benchmark and comparison of tracker-blockers: Should you trust them?

People are getting more and more conscious and worried about privacy issues that arise when browsing the Web. Ad-blockers, anti-tracking extensions, privacy and anonymity plug-ins, etc. promise to protect users and their privacy from third-party tracking systems. But how effective are they? In this paper, we present the first experimental campaign aimed at benchmarking popular plug-ins for web privacy preservation to date. We select 7 different plug-ins and setup a testbed to automatically browse regular web pages, while collecting navigation data. We analyze this data to compare each plugin, considering both privacy-protection and performance angles. Our results show that the picture is very variable, with no plugin being able to guarantee complete protection while improving performance as promised. By considering different experimental setups, we also observe that the European ePrivacy Directive is ignored by the majority of considered web sites. The directive prevents web services from installing tracking and profiling cookies before explicit consent is given by the user, but apparently this is not observed for most of services. To favor reproducibility, and repeatability, we share both the software and the data used to conduct this study with the community. Our aim is to let researchers and developers better understand the privacy threats in the Internet, possibly toward better performing privacy-preserving tools.