[tbb-bugs] #24351 [Applications/Tor Browser]: Block Global Active Adversary Cloudflare

Tor Bug Tracker & Wiki blackhole at torproject.org
Sun Nov 19 23:27:39 UTC 2017

#24351: Block Global Active Adversary Cloudflare
 Reporter:  nullius                              |          Owner:  tbb-
                                                 |  team
     Type:  enhancement                          |         Status:  new
 Priority:  High                                 |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  security, privacy, anonymity, mitm,  |  Actual Points:
  cloudflare                                     |
Parent ID:  #18361                               |         Points:
 Reviewer:                                       |        Sponsor:

Comment (by cypherpunks):

 HTTPS Cloudflare is MITMed.
 HTTP Cloudflare is MITMed(proxied via company with zero TLS protection).

 Cloduflare proxied websites must be blocked.

 1) Block Cloudflare certificates as untrusted. Treat it as self-signed.
 2) Block certificate if CN is "^(.*)\.cloudflaressl\.com".
 3) Block if "CF-Cache-Status:" or "CF-RAY:" header is found in the

 If 1, 2, 3 is true | then | raise "Unsecure Connection" error.

Ticket URL: <https://trac.torproject.org/projects/tor/ticket/24351#comment:5>
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