[tor-bugs] #16659 [- Select a component]: TCP Initial Sequence Numbers Leak Host Clock

Tor Bug Tracker & Wiki blackhole at torproject.org
Sun Jul 26 18:12:46 UTC 2015


#16659: TCP Initial Sequence Numbers Leak Host Clock
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     Reporter:  source                |      Owner:
         Type:  defect                |     Status:  new
     Priority:  normal                |  Milestone:
    Component:  - Select a component  |    Version:
   Resolution:                        |   Keywords:
Actual Points:                        |  Parent ID:
       Points:                        |
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Comment (by yawning):

 So patch your kernel?  I'm not seeing why this is a Tor issue, beyond "if
 you switch to using a UDP based transport, this will be a non-issue".

 Your Guard, or anyone that sits between you and your Guard knows who you
 are.  Leaking the delta of a timer that is on a 274s period with 64 ns
 resolution doesn't seem like a big deal.  Real time in ns is shifted,
 truncated, then added to a salted hash to derive the ISN, so it's not like
 it's possible to work backwards to the real time (or for that matter the
 original timer value) in any way, the best you can do is obtain load
 information via clock skew.

 I'm tempted to NAB this unless someone tells me otherwise.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16659#comment:6>
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