[tbb-bugs] #21559 [Applications/Tor Browser]: Tor browser deanonymization/fingerprinting via cached intermediate CAs

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#21559: Tor browser deanonymization/fingerprinting via cached intermediate CAs
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     Reporter:  cypherpunks          |      Owner:  tbb-team
         Type:  defect               |     Status:  new
     Priority:  Medium               |  Milestone:
    Component:  Applications/Tor     |    Version:
  Browser                            |   Keywords:  tbb-fingerprinting,
     Severity:  Normal               |  tbb-linkability
Actual Points:                       |  Parent ID:
       Points:                       |   Reviewer:
      Sponsor:                       |
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 Hi,

 I get different results testing https://fiprinca.0x90.eu/poc/ in a fresh
 Tor browser than in the Tor browser I've been using to browse the web for
 a bit.  (Both are running as Qubes disposable VMs so I haven't tested
 persistence).

 Expected behaviour: my Tor browser (version "6.5, based on Mozilla Firefox
 45.7.0") should not leak information about what sites I've visited.

 Actual behaviour: I see four cached CAs in the "warmed" browser, leaking
 information about what sites I've visited.

 Version: 6.5

 https://shiftordie.de/blog/2017/02/21/fingerprinting-firefox-users-with-
 cached-intermediate-ca-certificates-fiprinca/ has a writeup by the author.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21559>
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