[tor-bugs] #4392 [Tor Bridge]: UpdateBridgesFromAuthority is problematic

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#4392: UpdateBridgesFromAuthority is problematic
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 Reporter:  Sebastian   |          Owner:                  
     Type:  defect      |         Status:  new             
 Priority:  normal      |      Milestone:  Tor: unspecified
Component:  Tor Bridge  |        Version:                  
 Keywords:              |         Parent:                  
   Points:              |   Actualpoints:                  
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 When UpdateBridgesFromAuthority is set to 1, Tor makes a direct connection
 to Tonga to fetch the bridge descriptor referenced in the configuration,
 as long as it includes the fingerprint. This happens before even trying
 the bridge directly, so we definitely leak to censors that a) we're a tor
 client, trying to use bridges; and b) that we'll soon connect to a real
 bridge IP:port. Back when Tonga wasn't blocked, this seemed fine, but now
 that we have adversaries that actually pick up on the Tor handshake or
 network behavior and send active probes, this seems like a poor idea.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4392>
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