[tor-bugs] #20416 [Core Tor/Tor]: The Effect of DNS on Tor's Anonymity
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Fri Oct 21 06:16:34 UTC 2016
#20416: The Effect of DNS on Tor's Anonymity
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Reporter: ufd33 | Owner:
Type: project | Status: new
Priority: Very High | Milestone: Tor: unspecified
Component: Core Tor/Tor | Version: Tor: unspecified
Severity: Critical | Keywords:
Actual Points: | Parent ID:
Points: | Reviewer:
Sponsor: |
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We show how an attacker can use DNS requests to mount highly precise
website fingerprinting attacks: Mapping DNS traffic to websites is highly
accurate even with simple techniques, and correlating the observed
websites with a website fingerprinting attack greatly improves the
precision when monitoring relatively unpopular websites. Our results show
that DNS requests from Tor exit relays traverse numerous autonomous
systems that subsequent web traffic does not traverse. We also find that a
set of exit relays, at times comprising 40% of Tor’s exit bandwidth, uses
Google’s public DNS servers—an alarmingly high number for a single
organization. We believe that Tor relay operators should take steps to
ensure that the network maintains more diversity into how exit relays
resolve DNS domains.
full text:
We show how an attacker can use DNS requests to mount highly precise
website fingerprinting attacks: Mapping DNS traffic to websites is highly
accurate even with simple techniques, and correlating the observed
websites with a website fingerprinting attack greatly improves the
precision when monitoring relatively unpopular websites. Our results show
that DNS requests from Tor exit relays traverse numerous autonomous
systems that subsequent web traffic does not traverse. We also find that a
set of exit relays, at times comprising 40% of Tor’s exit bandwidth, uses
Google’s public DNS servers—an alarmingly high number for a single
organization. We believe that Tor relay operators should take steps to
ensure that the network maintains more diversity into how exit relays
resolve DNS domains.
full text:
https://nymity.ch/tor-dns/tor-dns.pdf
webpage:
https://nymity.ch/tor-dns/
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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20416>
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