Tracking The Impact of the WhatsApp Blockage on Tor

On May 2, 2016, a Brazilian judge ordered cell phone carriers to block access to the messaging service WhatsApp for 72 hours. The order applied to the whole nation of Brazil—100 million WhatsApp users. Worldwide, Internet censorship events happen frequently. They may occur in countries like Brazil or in oppressive regimes like Egypt or Saudi Arabia. We want to understand better what happens during these events.

If we can watch certain data points, we can observe, for instance, whether or not our tools are efficiently circumventing such blockages. The Tor Project has a set of tools that can help us learn these answers. We can not only identify whether a censorship event has happened, but see how it was accomplished by the censor, and observe if people are using our tool to bypass it.

The Open Observatory of Network Interference (OONI) is a Tor project focused on detecting censorship, surveillance, and traffic manipulation on the Internet. For the recent WhatsApp case, OONI published a report showing that the Brazilian mobile carriers blocked WhatsApp’s website through DNS hijacking.

OONI was able to determine this by running two tests on Brazil's network:
• DNS-consistency tests
• HTTP-request tests

While OONI tests are not currently designed to directly test instant messaging (IM) protocols, OONI did monitor access to the WhatsApp website. This data allows us to analyze the censorship mechanisms used, and to determine if tools like Tor can bypass the block.

In this case, an Android user could download Orbot, a Tor proxy tool for Android, and successfully bypass the censorship with its VPN mode.

As soon as the blockade was announced, we began promoting key tips in Portuguese on social media and elsewhere to instruct Brazilians about how to bypass the WhatsApp blockage on Android with Orbot.

For Orbot statistics, we don't use Google Analytics or other system to track Orbot users, other than what Google Play can show us about installs and uninstalls. Based only on that, Orbot's active install for Brazil on May 1st was at 33,458. On May 2nd it went up to 41,333.

Taking a look at the number of downloads for Orbot in Brazil, we saw a 20% to 30% increase in the rate of downloading on those days.

There was a similar increase on the Tor network, where the average number of daily direct connected users for Brazil, went from ~50,000 to 60,000 in 24 hours.

Our metrics.torproject.org portal, which hosts data visualizations from our network, also caught the circumvention event. The little blue dot represents the fact that something is happening in the region. Is great to see that even for very sudden and short-lived actions (the block was lifted in Brazil after about 24 hours), we were still capable of capturing it in our data. You can read here about how we do it and the precautions we take while collecting such data so we don't affect user privacy.

We know that we are talking about a small number of users in a world of 100 million, in the case of WhatsApp. There is still a lot of work to be done to help people become aware of such tools. However, it is great to see our projects coming together to tell this story.

Our experience with the WhatsApp blockage in Brazil demonstrates the potential these efforts have to provide us with information about censorship events and to help us build circumvention mechanisms against them.

We are working hard on new features for these tools; for instance, we want to deploy more mobile network tests for OONI and better visualizations of our data so that others can easily explore and learn from them, and we continue to improve user experience on our apps. Keep an eye on this blog as we develop this work!