OONIDetectingBlockingOfThirdPartyApps

Possible strategies

1. Doing reachability testing for the endpoints of the app (pros: low effort to implement, relatively easy to update when things change cons: not accurate when the blocking is not simply hostname/ip:port based)

2. Doing something where we collect a PCAP of how the traffic of a given app works and replay the traffic towards our control servers (pros: medium effort to implement, once implemented it can easily be extended to an arbitrary app cons: only accurate when blocking is protocol based)

3. Implementing the real protocol of the app and speaking it with the servers (pros: most accurate as it would tell us for sure when a given app is working or not working cons: high effort to implement, needs to be implemented indepedently for every app, requires reversing of the app, need to update the app every time it changes)

4. Setup a VPN on the probe end and route traffic from a real app in our censorship testbed (pros: medium effort to implement cons: can be complex to scale this approach to many measurement clients, requires setting up dedicated serverside infrastructure to run the measurements)

5. Have the user run the app, but route the traffic of the app via a VPN setup on the device and detect the blocking inside of the VPN. (pros: medium effort to implement, cons: requires user intervention, may not be possible on every platform)

Existing apps using approach 3.

Differentiator detector: http://dd.meddle.mobi/

Glasnost: http://broadband.mpi-sws.org/transparency/glasnost.php

Existing apps using approach 5.

Haystack: https://haystack.mobi/

** Key takeaways **

• Standalone application to collect the data vs integrating inside of other pieces of software.

• Application that detects blocking on mobile and tries different strategies to get around the blocking.

• Could be a way to foster collaboration amongst CCT vendors.

• Possibility of doing the same thing for Firefox.