[tbb-bugs] #16132 [Tor Browser]: Session restore allows fingerprinting of users by choice of open tabs

[Tor Bug Tracker & Wiki]

#16132: Session restore allows fingerprinting of users by choice of open tabs
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 Reporter:  vynX         |          Owner:  tbb-team
     Type:  defect       |         Status:  new
 Priority:  normal       |      Milestone:
Component:  Tor Browser  |        Version:
 Keywords:               |  Actual Points:
Parent ID:               |         Points:
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 This is a Firefox privacy problem that so far has not been considered of
 interest for Tor Browser since only "Private Browsing" is considered safe.

 Many day-to-day users like to enjoy Tor Browser for its anonymization,
 reduced tracking and improved Javascript security but they are not
 paranoid about the security of their own computer, thus they don't enable
 Private Browsing all the time and prefer to enjoy the convenience of a
 browser that helps you do your everyday work (history completion, leaving
 tabs open for later etc).

 Thus they will find themselves experiencing a browser or computer crash
 and be thankful to recover all the tabs when reopening the browser. The
 privacy bugfix that would be useful at this point is to modify Firefox's
 session resume in such a way that not only the tabs are loaded when
 accessed (which is already the default) but to also not access all the
 sites in the tabs just to have a neat favicon to display (considering also
 that the disk cache should have them already).

 All there is to do is to disallow those outgoing HTTP requests during
 session restore.

 Possibly related to #15781 or #10400.

 This comes in a series of bug/enhancement requests relating to the purpose
 of making Tor Browser also support the bulk surveillance threat model, not
 just the targeted surveillance threat model (which includes distrusting
 the local computer and hard disk). In order to address bulk surveillance,
 Tor Browser needs to become an acceptable choice for mainstream users and
 work on its market share. This is reasonable because none of the existing
 mainstream browsers fill that role, they all support the surveillance
 apparatus.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16132>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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