[tor-bugs] #2873 [Tor bundles/installation]: Block Components.lookupMethod in TorBrowser

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#2873: Block Components.lookupMethod in TorBrowser
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 Reporter:  mikeperry                 |          Owner:  mikeperry
     Type:  enhancement               |         Status:  new      
 Priority:  normal                    |      Milestone:           
Component:  Tor bundles/installation  |        Version:           
 Keywords:                            |         Parent:  #2871    
   Points:                            |   Actualpoints:           
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 It appears that EMCAScript 5 added official support for hooking JS objects
 for protection against XSS. However Firefox seems to have left a backdoor
 to undo these hooks in the form of Components.lookupMethod, which is
 marked "unconfigurable" (which means it cannot be hooked).

 We should remove this bit, and/or neuter this API in TorBrowser. This
 should allow us to safely write JS hooks to deal with fingerprinting
 issues in the window object and the DOM.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/2873>
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