[tor-bugs] #10969 [Core Tor/Tor]: Set of guard nodes can act as a linkability fingerprint

[Tor Bug Tracker & Wiki]

#10969: Set of guard nodes can act as a linkability fingerprint
-------------------------------------------------+-------------------------
 Reporter:  asn                                  |          Owner:
                                                 |  mikeperry
     Type:  defect                               |         Status:
                                                 |  reopened
 Priority:  High                                 |      Milestone:  Tor:
                                                 |  unspecified
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-client, tor-guard, XKEYSCORE,    |  Actual Points:
  prop259, SponsorU-deferred, QUICKANT           |
Parent ID:                                       |         Points:  large
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
Changes (by cypherpunks):

 * status:  closed => reopened
 * resolution:  fixed =>


Comment:

 Hi isis, I'm again reopening this ticket because the fundamental problem
 in the title and description ("set of guard nodes can act as a linkability
 fingerprint") remains unfixed.

 I just checked a friend's laptop (Debian stable, tor 0.2.9.11-1~deb9u1)
 and when it got online it immediately connected to four guards. I don't
 know why, but I suspect it's because (like most laptops) it is sometimes
 not connected to the internet. (Some time later, it remained connected to
 two of them.)

 I'm well aware of other possible infoleaks and fingerprinting vectors, and
 I am even beta-testing a DHCP client that implements RFC7844. But even for
 casual users without a randomized MAC address and restrictive firewall, it
 seems obvious that tracking a person as they change locations is much
 simpler when there's a unique set of IPs which they (and only they)
 connect to, doesn't it?

 Btw, your fork of tordyguards which you linked above is
 [https://github.com/isislovecruft/tordyguards/compare/master...leewoboo:master
 currently missing three commits from upstream from 2014] so I think I'll
 stick with that version for now.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/10969#comment:40>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online