Announcing Tor Reports

For the past four years, I've been summarizing progress of Tor on the blog. See the tag progress report for the history of these reports. Based on community feedback, we're switching to a mailing list with archive of the raw status reports. Tor-reports is live. The goal is to provide the raw details rather than summarizing all of the progress and only being able to provide a quick summary per topic.

Each developer, advocate, and internal staff will be posting their reports to this list. The idea is to share more with the community and give people a chance to ask questions directly of the people doing the work. Enjoy the transparency.

Florence Hackfest Thanks

Thanks to all who attended and helped make the hackfest in Florence a success. Around 50 people stayed for the two day event. We heard from a team working on a free hardware and software (firmware to drivers) laptop prototype, some Italian legal experts with regards to anonymity, encryption, and chilling effects used to great length in the country, plus a number of Italian hackers from EuroPython 2012 interested in Tor (and vice versa).

And a big thanks to the Università degli Studi di Firenze, Il Progetto Winston Smith and Arturo for their translations, coordinations, and general welcoming attitude to Italy.

Security vulnerability found in Cyberoam DPI devices (CVE-2012-3372)

Last week, a user in Jordan reported seeing a fake certificate for The user did not report any errors when browsing to sites such as Gmail, Facebook, and Twitter, which suggests that this was a targeted attack. The certificate was issued by a company called Cyberoam. We first believed that this incident was similar to that of Comodo and DigiNotar, and that Cyberoam had been tricked to issue a fake certificate for our website.

After a bit of research, we learned that Cyberoam make a range of devices used for Deep Packet Inspection (DPI). The user was not just seeing a fake certificate for, his connection was actually being intercepted by one of their devices. While investigating this further, Ben Laurie and I found a security vulnerability affecting all Cyberoam DPI devices.

Examination of a certificate chain generated by a Cyberoam DPI device shows that all such devices share the same CA certificate and hence the same private key. It is therefore possible to intercept traffic from any victim of a Cyberoam device with any other Cyberoam device - or to extract the key from the device and import it into other DPI devices, and use those for interception.

Ben and I wrote a security advisory and notified Cyberoam of this vulnerability at 17:00 UTC on Saturday, June 30. We made it clear that we intended to publish this blog post and the security advisory on Tuesday, July 3, and encouraged them to respond promptly if they had any comments. At the same time, we notified browser vendors and asked that they blacklist the Cyberoam CA certificate in their browsers.

Cyberoam have not yet commented on this issue, apart from acknowledging our first email and saying that they are looking into it. The Cyberoam CA certificate is not trusted, and so browsers will show users a warning (unless someone has already installed the certificate). Users with the Tor Browser Bundle are not affected.

To check if this CA is installed in your browser, see the following instructions for Internet Explorer, Firefox, Chrome, and Safari. The instructions mention DigiNotar, but they are still valid. If you have more information about this issue, please email

2012 Florence Hackfest

On July 5 and 6 we are holding an open hackfest at the Università degli Studi di Firenze in Florence, Italy.

Please attend if you have some interest in programming, advocacy, marketing, or (network security/anonymity/computer science/etc) research with Tor, or are willing to be persuaded to entertain an interest. :) Tor's a small project (in terms of number of developers) that could really use your help.

The majority language will be English, but there will be some Italian speakers at the hackfest.

More details can be found on the Florence Hackfest wiki page.

See you in Florence!

New Tor Browser Bundles

The Tor Browser Bundles have been updated with a bunch of new software: Tor, Vidalia 0.2.19, and we have switched to using Firefox's long-term stable release (10.0.5esr).

Tor Browser Bundle (2.2.37-1)

  • Update Tor to
  • Switch Firefox to 10.0.5esr, since we will be tracking the extended stable releases for TBB stable versions
  • Update Vidalia to 0.2.19
  • Update Torbutton to 1.4.6
  • Update NoScript to 2.4.4

New Tor Browser Bundles

The Tor Browser Bundles and other packages have all been updated to the latest Tor stable version.

Tor Browser Bundle (2.2.36-1)

  • Update Tor to
  • Update NoScript to 2.3.4
  • Update HTTPS Everywhere to 2.0.5

An update on the censorship in Ethiopia

A few days ago, we published a blog post exposing the use of Deep Packet Inspection (DPI) to filter all Internet traffic in Ethiopia, including connections to the Tor network. We concluded that they are doing some sort of TLS fingerprinting, but had not been able to figure out exactly what they are fingerprinting on. Since then, we have managed to determine exactly how Ethiopia blocks Tor and we have developed a workaround. We will publish a full technical analysis very soon.

The long-term solution for Tor users in Ethiopia is to use the Obfsproxy Tor Browser Bundle. The bundles are, unfortunately, not up to date at the moment, but this is something we are working on (see #5937 for details). In the meantime, try using one of the following three bridges:

If the bridges are not working, or you have questions, send an email to

Ethiopia Introduces Deep Packet Inspection

The Ethiopian Telecommunication Corporation, which happens to be the sole telecommunication service provider in Ethiopia, has deployed or begun testing Deep Packet Inspection (DPI) of all Internet traffic. We have previously analyzed the same kind of censorship in China, Iran, and Kazakhstan.

Reports show that Tor stopped working a week ago -- even with bridges configured. Websites such as,,, and even continue to work. The graphs below show the effects of this deployment of censorship based on Deep Packet Inspection:

An analysis of data collected by a volunteer shows that they are doing some sort of TLS fingerprinting. The TLS server hello, which is sent by the Tor bridge after the TLS client hello, never reaches the client. We don't know exactly what they are fingerprinting on, but our guess is that it is either the client hello or the server hello. An illustration can be found in this network flow diagram.

Thanks to Philipp Winter and George Kadianakis for helping me analyze the data. If you have more information about the censorship in Ethiopia, please email

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