Khattak, S;
Fifield, D;
Afroz, S;
Javed, M;
Sundaresan, S;
Paxson, V;
Murdoch, SJ;
(2016)
Do You See What I See? Differential Treatment of Anonymous Users.
In:
Proceedings of the NDSS Symposium 2016.
Internet Society
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Abstract
The utility of anonymous communication is undermined 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 service’s 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 Internetwide 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.
| Type: | Proceedings paper |
|---|---|
| Title: | Do You See What I See? Differential Treatment of Anonymous Users |
| Event: | NDSS Symposium’16 |
| Location: | San Diego, CA, US |
| Dates: | 21 February 2016 - 24 February 2016 |
| ISBN: | 1-891562-41-X |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.14722/ndss.2016.23342 |
| Publisher version: | http://dx.doi.org/10.14722/ndss.2016.23342 |
| Language: | English |
| Additional information: | This version is the published version. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Computer Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1472066 |
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