Title
Do You See What I See? Differential Treatment of Anonymous Users.
Abstract
The utility of anonymous communication is un- dermined by a growing number of websites treating users of such services in a degraded fashion. The second-class treatment of anonymous users ranges from outright rejection to limiting their access to a subset of the serviceu0027s functionality or imposing hurdles such as CAPTCHA-solving. To date, the observation of such practices has relied upon anecdotal reports catalogued by frustrated anonymity users. We present a study to methodically enumerate and characterize, in the context of Tor, the treatment of anonymous users as second-class Web citizens. We focus on first-line blocking: at the transport layer, through reset or dropped connections; and at the application layer, through explicit blocks served from website home pages. Our study draws upon several data sources: comparisons of Internet- wide port scans from Tor exit nodes versus from control hosts; scans of the home pages of top-1,000 Alexa websites through every Tor exit; and analysis of nearly a year of historic HTTP crawls from Tor network and control hosts. We develop a methodology to distinguish censorship events from incidental failures such as those caused by packet loss or network outages, and incorporate consideration of the endemic churn in web-accessible services over both time and geographic diversity. We find clear evidence of Tor blocking on the Web, including 3.67% of the top-1,000 Alexa sites. Some blocks specifically target Tor, while others result from fate-sharing when abuse-based automated blockers trigger due to misbehaving Web sessions sharing the same exit node.
Year
Venue
Field
2016
NDSS
Application layer,Internet privacy,Censorship,Computer science,Computer security,Packet loss,Transport layer,Anonymity,Limiting,The Internet
DocType
Citations 
PageRank 
Conference
12
0.65
References 
Authors
6
8
Name
Order
Citations
PageRank
Sheharbano Khattak1745.32
David Fifield2342.32
Sadia Afroz3202.16
Mobin Javed411811.18
Srikanth Sundaresan5131.00
damon mccoy62073125.49
Vern Paxson7140312130.20
Steven J. Murdoch880657.90