[tor-bugs] #18450 [Tor Browser]: JavaScript can reveal the OS.

[Tor Bug Tracker & Wiki]

#18450: JavaScript can reveal the OS.
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 Reporter:  cypherpunks  |          Owner:  tbb-team
     Type:  defect       |         Status:  new
 Priority:  Medium       |      Milestone:
Component:  Tor Browser  |        Version:
 Severity:  Normal       |     Resolution:
 Keywords:               |  Actual Points:
Parent ID:               |         Points:
  Sponsor:               |
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Comment (by cypherpunks):

 Currently, there are several ways to detect the platform. No Javascript is
 required.

 The font sets/whitelisted fonts are different. TBB uses the native font
 rendering engine - different for each platform. The UI controls are
 different (things like scrollbars, checkboxes, input fields). These
 differences can all be detected with CSS, no Javascript required.

 Keyboard events are different. Resources (resource:// URIs can be be used
 to access various local resources) are different - that's what
 Browserleaks is using.

 There likely is more stuff.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/18450#comment:1>
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