[tor-bugs] #15951 [Tor]: FairPretender: Pretend as any hidden service in passive mode

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#15951: FairPretender: Pretend as any hidden service in passive mode
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 Reporter:  twim                 |          Owner:  twim
     Type:  defect               |         Status:  new
 Priority:  major                |      Milestone:
Component:  Tor                  |        Version:
 Keywords:  tor, hs, descriptor  |  Actual Points:
Parent ID:                       |         Points:
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 This flaw in in Tor protocol provides a possibility to resign any Hidden
 Service descriptor with one’s private key. Thus an adversary that does so
 can upload this resigned descriptor to the HS Directory and act as a
 frontend to hidden services whose Introduction Point data has been
 resigned. They can spread the .onion address of his frontend Hidden
 Service as a real one over the Internet (phishing) and then perform a DoS
 attack on chosen Hidden Services or redirect traffic to replicas that he
 controls and perform Man-in-the-Middle attack.

 This is just a brief explanation. For more info see attached paper.

 I have idea how to fix this by introducing "backward permanent key
 signature"
 https://github.com/mark-in/tor/tree/backward-permkey-signature
 https://github.com/mark-in/torspec/tree/backward-permkey-signature

 It would be great to hear more ideas from you how to fix it better.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/15951>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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