[tor-bugs] #32135 [Circumvention/BridgeDB]: Write BridgeDB metrics parser and analyse existing data

Tor Bug Tracker & Wiki blackhole at torproject.org
Tue Oct 22 22:25:12 UTC 2019


#32135: Write BridgeDB metrics parser and analyse existing data
------------------------------------+--------------------------
 Reporter:  phw                     |          Owner:  phw
     Type:  task                    |         Status:  assigned
 Priority:  Medium                  |      Milestone:
Component:  Circumvention/BridgeDB  |        Version:
 Severity:  Normal                  |     Resolution:
 Keywords:  s30-o21a1               |  Actual Points:
Parent ID:  #31274                  |         Points:  2
 Reviewer:                          |        Sponsor:
------------------------------------+--------------------------

Comment (by phw):

 Below are a bunch of diagrams that I created from our BridgeDB usage
 metrics. The scripts that I used to create these diagrams are available
 here: https://dip.torproject.org/phw/bridgedb-metrics-visualisation

 Note that none of the diagrams below contains vanilla bridges because of a
 bug (#32203). (In fact, I discovered this bug by glancing at these
 visualisations and wondering why there are no vanilla bridges.)

 == Requests per bridge types

 [[Image(bridge-types.png, 600px)]]

 [[Image(bridge-types-nontor.png, 600px)]]

 The first diagram suggests that ScrambleSuit and obfs3 are relatively
 popular but once we remove HTTPS requests coming from Tor (which we
 believe to be almost entirely bots), basically only obfs4 remains. Note
 that this visualisation is an aggregate over all distribution mechanisms.
 An average of ~7,500 obfs4 requests per day is a surprisingly large number
 to me. There may very well be more bots among these requests.

 == Requests per distribution mechanism

 [[Image(distribution-mechanisms.png, 600px)]]

 [[Image(distribution-mechanisms-notor.png, 600px)]]

 Again, we can see a significant difference between all requests and
 requests without bots. With bots removed, moat is our most active
 distribution mechanism. Note that in moat it's difficult to tell apart a
 user from a bot request, so this visualisation is assuming that all
 requests are from users, which is probably false.

 == (Un)successful requests per distribution mechanism

 [[Image((un)successful-email.png, 600px)]]

 Most users (assuming that these requests are in fact from users) succeed
 at getting bridges over email. The drop in mid-October was because of a
 bug in BridgeDB (#32105).

 [[Image((un)successful-moat.png, 600px)]]

 Moat is looking worse. A sizable fraction of requests are unsuccessful,
 presumably because of the difficulty of our CAPTCHA.

 [[Image((un)successful-nontor-https.png, 600px)]]

 The situation is similar for HTTPS requests excluding requests over Tor
 (which we believe are bots).

 [[Image((un)successful-tor-https.png, 600px)]]

 HTTPS requests over Tor only are surprisingly successful. These bots are
 likely using a classifier that solves our CAPTCHAs.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/32135#comment:1>
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