Tor Weekly News — February 12th, 2014

Lunar lunar at
Wed Feb 12 13:32:33 UTC 2014

Tor Weekly News                                      February 12th, 2014

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

Tails 0.22.1 is out

The Tails team cut its 36th release on February 4th. Their Debian-based
live operating system continues to provide anonymity by ensuring that
all outgoing connections are routed through Tor, and privacy by ensuring
that no traces are left without the user’s knowledge.

Tails 0.22.1 [1] contains security fixes [2] to Firefox, NSS, and
Pidgin. It also brings an updated Linux kernel and several fixes for
regressions and small issues.

While advertised as a minor version, the new incremental upgrades are a
major usability improvement. Previously, upgrading Tails basically meant
installing Tails again by downloading the image and putting it on a DVD
or a USB stick. Users who store persistent data in their Tails instance
then had to use this new medium to upgrade the stick with their data. A
tedious process, to say the least. Now, with incremental upgrades, Tails
users with USB sticks will be prompted to perform a few clicks, wait,
and reboot to get their system up-to-date.

One usability change might surprise long time Tails users: the browser
now has to be manually opened when Tor has successfully reached the

As always, be sure to upgrade [3]! Users of Tails 0.22 on USB sticks can
do so easily by running the “Tails Upgrader” application in the “Tails”


Tor Browser Bundle 3.5.2 is released

The Tor Browser team delivers a new Tor Browser Bundle [4]. Version
3.5.2 brings Tor users important security fixes from Firefox [5] and
contains fixes to the “new identity” feature, window size rounding, and
the welcome screen with right-to-left language, among others.

The curious can take a peek at the changelog [6] for more details.
Every Tor user is encouraged to upgrade as soon possible. Jump to the
download page [7]!


Call to bridge operators to deploy ScrambleSuit

In the beginning there was Tor. When censors started filtering every
known relay address, bridges [8] were invented as a way to access the
Tor network through unlisted relays. Deep packet inspection systems then
started to filter Tor based on its traffic signature, so pluggable
transports [9] and obfucation protocols were designed in order to
prevent bridge detection.

Currently, obfuscation is achieved through “obfs2” and “obfs3”. obfs2 is
flawed; it’s detectable by deep packet inspection and is being phased
out. obfs3 is unfortunately still vulnerable to active probing attacks.
As obfs3 bridges are open to anyone, an attacker who uses a traffic
classifier and finds an unclassified connection can figure out if it’s
Tor simply by trying to connect through the same destination.

ScrambleSuit [10] comes to the rescue. On top of making the traffic
harder to recognize by timing or volume characteristics, ScrambleSuit
requires a shared secret between the bridge and the client. A censor
looking at the connection won’t have this secret, and therefore be
unable to connect to the bridge and confirm that it’s Tor.

obfsproxy 0.2.6 was released last week [11] and adds ScrambleSuit to the
set of available pluggable transports. Bridge operators are now
called [12] to update their software and configuration. At least Tor is required. The latest version of obfsproxy can be
installed from source [13], pip [14] and Debian unstable [15].

There must be a critical mass of bridges before ScrambleSuit is made
available to the Tor users who need it, so please help!


More status reports for January 2014

The wave of regular monthly reports from Tor project members for the
month of January continued. Kevin P Dyer [16], Nick Mathewson [17],
Georg Koppen [18], Karsten Loesing [19], Jacob Appelbaum [20], Arturo
Filastò [21], Isis Lovecruft [22] and Nicolas Vigier [23] all released
their reports this week.

Roger Dingledine has also sent the report [24] to SponsorF.


Miscellaneous news

Most Tor developers will gather next week in Reykjavík, Iceland for the
2014 winter meeting [25]. Expect a drop in activity on the usual
communication channels while everyone is busy with face-to-face
conversations. See upcoming events below for activities open to the
larger Tor community.


David Fifield is looking for testers [26] for experimental 3.5.2 browser
bundles with tor-fw-helper. “tor-fw-helper is a tool that uses UPnP or
NAT-PMP to forward a port automatically” — something that
flashproxy [27] requires. David is “interested in finding out how likely
it is to work”.


David Goulet gave us an update on the development of Torsocks 2.x [28].
He hopes to perform a “full on release” after the Tor developers


”The Trying Trusted Tor Traceroutes project is coming closer to the next
data review (03/2014)” wrote [29] Sebastian Urbach. If you are a relay
operator, please help find out how Tor performs against network-level
attackers. The team now has a scoreboard [30] with feedback for the


One relay started to act funny regarding its advertised bandwidth. Roger
Dingledine quickly reported his worries [31] to the tor-talk mailing
list. A couple of hours later Hyoung-Kee Choi accounted [32] that one of
the students from his research group had made a mistake while
experimenting on the Tor bandwidth scanner. Directory authorities are
now restricting its usage in the consensus.


On February 11th, the Tor Project participated on “The Day We Fight
Back” [33], a global day of mobilization against NSA mass surveillance.


Tor help desk roundup

Tor supporters are often curious about the legal risks involved in
running a Tor relay. The Tor Project is not aware of any country where
running Tor is a punishable offense. Running a bridge relay or a
non-exit relay is the best way to grow the Tor network without being
exposed to additional legal scrutiny. The decision to run an exit relay
should be made only after carefully reviewing the best practices [34].
Unlike non-exit and bridge operators, exit relay operators need to be
prepared to respond to abuse complaints.

Users continue to express interest in a 64-bit Tor Browser Bundle for
Windows. Work to provide this new variant is on-going [35].


News from Tor StackExchange

strugee is running a Fast, Running and Valid relay and wonders when the
relay will get the V2Dir flag [36]. weasel answered that relays should
“get the V2Dir flag simply by publishing a DirPort”, but that Tor will
not always publish a DirPort: the full list can be found in the source
code [37].


Ivar noted that the site How’s my SSL [38] thinks that the SSL
configuration of the Tor Browser is bad and wondered how the situation
could be improved [39]. Jens Kubieziel explained some settings for
about:config and pointed to a more detailed blog post [40]. Sam Whited
also pointed out some settings for Firefox and noted that Firefox 27
improved the rating to “probably good” [41] which will help the Tor
Browser in the future.


fred set up a relay on a Windows machine where µTorrent is used besides
Tor. When Tor is enabled many trackers become unreachable, but come back
as soon as the relay is disabled. An explanation to this behaviour [42]
has yet to be found, don’t hesitate to chime in.


Upcoming events

Feb 18 20:00 | Crypto Party at Múltikúlti
             | Reykjavík, Iceland
Feb 19 18:30 | Talk: “Tor: Lessons Learned over the past 12 months”
             | Reykjavík University M101, Iceland
Feb 20  9:00 | Digital Safety for Journalists — ½ day hands-on workshop
             | Grand Hotel, Reykjavík, Iceland
Feb 21  9:30 | Tor public hack day
             | Grand Hotel, Reykjavík, Iceland

This issue of Tor Weekly News has been assembled by Lunar, Matt Pagan,
Paul Feitzinger, qbi, Roger Dingledine and Karsten Loesing.

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 [43], write down your
name and subscribe to the team mailing list [44] if you want to
get involved!

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