Tor Weekly News — January 29th, 2014

Lunar lunar at
Wed Jan 29 12:25:10 UTC 2014

Tor Weekly News                                       January 29th, 2014

Welcome to the fourth issue of Tor Weekly News in 2014, the weekly
newsletter that covers what is happening in the Tor community.

Tor Browser Bundle 3.5.1 is released

An update to the Tor Browser Bundle has been released [1] on January
27th. The new release contains Tor which fixes a bug [2]
creating useless extra circuits. It also fixes a denial of service
condition in OpenSSL and removes “” from the NoScript

Arabic bundles are back after a short hiatus. Support for screen readers
is also enabled again and has been confirmed working [3].

HTTPS Everywhere has been updated to version 3.4.5. It contains a new
rule to secure connections to Stack Exchange and its Tor corner [4].

Look at the blog post for a more detailed changelog. And now, head over
to the download page [5] and upgrade!


New Tor denial of service attacks and defenses

Rob Jansen, Florian Tschorsch, Aaron Johnson, and Björn Scheuermann have
been working on a new paper [6] entitled “The Sniper Attack: Anonymously
Deanonymizing and Disabling the Tor Network”. As research papers are
sometimes hard to fully understand, Rob Jansen has published a new blog
post [7] giving an overview of the attacks, the defenses, what has been
modified in Tor so far, and what open questions remain.

“We found a new vulnerability in the design of Tor’s flow control
algorithm that can be exploited to remotely crash Tor relays. The attack
is an extremely low resource attack in which an adversary’s bandwidth
may be traded for a target relay’s memory (RAM) at an amplification rate
of one to two orders of magnitude” explains Rob.

The authors have been working with Tor developers on integrating
defenses before publishing: “Due to our devastating findings, we also
designed three defenses that mitigate our attacks, one of which provably
renders the attack ineffective. Defenses have been implemented and
deployed into the Tor software to ensure that the Tor network is no
longer vulnerable as of Tor version and later.”

Be sure to read the blog post and the paper in full if you want to know


Good times at Real World Crypto 2014

On the second week of January, a bunch of Tor developers attended the
Real World Crypto (RWC) workshop [8] in New York City.

The workshop featured a nice blend of industry and academic crypto talks
and a fruitful hallway track. Many researchers involved with Tor and
privacy technologies were also present.

As far as talks were concerned, Tom Shrimpton presented the
Format-Transforming Encryption (FTE) traffic obfuscation tool [9] which
is currently being developed to work as a Tor pluggable transport [10].
The Tor developers present also worked with Kevin Dyer, one of the paper
authors and developers of FTE, towards including FTE in the Pluggable
Transport Tor bundles.

On the censorship circumvention front, I2P developers showed interest in
using pluggable transports. Work has been done to identify various
problems with the current PT spec that need to be fixed so that other
projects can use pluggable transports more smoothly [11].

Furthermore, there were talks with the developers of UProxy [12] (a
censorship circumvention tool made by Google) and helped them understand
how pluggable transports work and what they would need to do if they
wanted to use them in UProxy. They seemed interested and motivated to
work on this.

The Tor developers also worked on the “Next Generation Hidden Services”
project [13], and sketched out some ways to move forward even though
there are some open research questions [14] with the current

Nick Mathewson commented on IRC: “I think the hallway track to main
conference utility ratio was higher than usual, since the conference
actually sticks practitioners and cryptographers in the same room pretty
reliably.” Let’s hope for next year!


The media and some terminology

BusinessWeek published “The inside story of Tor, the best Internet
anonymity tool the government ever built” [15]. Better that what one can
usually read about Tor in the press, the piece — courtesy of Dune
Lawrence — still sparkled a discussion on the tor-talk mailing list
about terminology [16].

Katya Titov quoted a misleading part of the article: “In addition to
facilitating anonymous communication online, Tor is an access point to
the ‘dark Web’, vast reaches of the Internet that are intentionally kept
hidden and don’t show up in Google or other search engines, […].”

As references to the “dark web”, the “deep web”, or the “dark deep shady
Knockturn Alley of the Internet” have been popping up more and more in
the media over the past months, Katya wanted to come up with proper
definitions of commonly misunderstood terms to reduce misinformation and
FUD [17].

She summarized the result of the discussion in a new
“HowBigIsTheDarkWeb” wiki page [18]. Be sure to point it to your fellow


Miscellaneous news

To follow up on last week’s Tor Weekly News coverage, Philipp Winter
wrote a blog post to explain “what the ‘Spoiled Onions’ paper means for
Tor users” [19].


Thanks to Sukhbir Singh, users with email addresses can now
request bridges and bundles via email [20].


Karsten Loesing dug some statistics [21] about the Tor Weather service.
There are currently 1846 different email addresses subscribed for 2349
Tor relays.


Tor developers will be present at the Mozilla booth during
FOSDEM’14 [22].  Drop by if you have questions or want to get involved
in Tor!


Tor help desk roundup

Users repeatedly contact Tor help desk about unreachable hidden
services. If that happens, please first make sure the system clock is
accurate and try to visit the hidden service for the Tor Project’s
website [23]. If it works, it means that Tor is working as it should and
there’s nothing more the Tor Project can do. Hidden services are solely
under the responsibility of their operators and they are the only one
that can do something when a hidden service goes offline.

  [23] http://idnxcnkne4qt76tg.onion/

News from Tor StackExchange

Alex Ryan has been experiencing crashes of his relay running on a
Raspberry Pi [24] due to circuit creation storms. He found out that the
problem disappeared after upgrading to the new 0.2.4 series of Tor.
There are currently no official Raspbian packages, so users will have to
build the package manually from source.


User cypherpunks wanted to know how to report security issues to the Tor
Project [25]. Until a proper process is decided [26], the best way at
the moment is to contact Nick Mathewson, Andrea Shepard, or Roger
Dingledine privately using their GnuPG keys.


How many hidden services can be served from a single Tor instance? [27]
Syrian Watermelon is looking to know if there is a hard limit and how
memory usage will go. The question is still open and has attracted some
interest from other users.


Upcoming events

Feb 1-2    | Tor @ FOSDEM
           | Brussels, Belgium
Feb 8      | Aaron @ New Media Inspiration 2014
           | Prague, Czech Republic
Feb 8      | Colin @ Winnipeg CryptoParty
           | Winnipeg, Canada

This issue of Tor Weekly News has been assembled by Lunar, George
Kadianakis, qbi, Karsten Loesing and dope457.

Want to continue reading TWN? Please help us create this newsletter.
We still need more volunteers to watch the Tor community and report
important news. Please see the project page [28], write down your
name and subscribe to the team mailing list [29] if you want to
get involved!

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <>

More information about the tor-news mailing list