[tor-bugs] #13155 [Tor]: I can use an extend cell to remotely determine whether two relays have a connection open

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#13155: I can use an extend cell to remotely determine whether two relays have a
connection open
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     Reporter:  arma    |      Owner:
         Type:  defect  |     Status:  new
     Priority:  normal  |  Milestone:  Tor: 0.2.???
    Component:  Tor     |    Version:
   Resolution:          |   Keywords:
Actual Points:          |  Parent ID:
       Points:          |
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Comment (by arma):

 Replying to [comment:2 Sebastian]:
 > won't timing give this away pretty reliably, too?

 Yes (probably) -- you could ask to connect to the right addr:port for the
 relay, and see if you succeed quickly or slowly.

 But in that case you're modifying the thing you're measuring. The above
 attack leaves it in whatever state it's in (e.g. so you can measure it
 again soon after).

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13155#comment:3>
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