Archive - 2008

Today, a team of security researchers and cryptographers gave a talk at the 25th Chaos Communication Congress (25C3), about a nifty attack against X.509 certificates generated using the MD5 digest algorithm. We figured that people will ask us about how this attack affects Tor, so I'm writing an answer in advance.

The short version: This attack doesn't affect Tor.

The medium version: This attack doesn't affect Tor, since Tor doesn't ever use MD5 certificates, and since Tor doesn't care what certificate authorities say. On the other hand, this attack probably does affect your browser. Check your browser vendor for updates over the next few days and weeks, and make sure you install them. read more »

Bug Fixes

Tor 0.2.1.7-alpha (released November 8) fixes a major security problem in Debian and Ubuntu packages (and maybe other packages) noticed by Theo de Raadt, fixes a smaller security flaw that might allow an attacker to access local services, adds better defense against DNS poisoning attacks on exit relays, further improves hidden service performance, and fixes a variety of other issues.
http://archives.seul.org/or/talk/Nov-2008/msg00229.html

Tor 0.2.0.32 (released November 20) fixes a major security problem in Debian and Ubuntu packages (and maybe other packages) noticed by Theo de Raadt, fixes a smaller security flaw that might allow an attacker to access local services, further improves hidden service performance, and fixes a variety of other issues.
http://archives.seul.org/or/announce/Dec-2008/msg00000.html

Vidalia 0.1.10 (released November 2) fixes some presentation bugs and some bugs in the Windows installer. read more »

We've published our three-year development roadmap. There are two main goals in publishing this document: first to be more transparent in what we're doing; and second to ask for help in improving everything related to Tor.

While we don't expect everyone will read through the roadmap start to finish, the Table of Contents provides a quick overview of the high-level goals. Each high-level goal is fairly independent of another, so you can simply read about the goals that interest you.

And for the first time ever, we've created a press release. This is our attempt to become more press friendly and provide a way for the media to start a conversation with us.

We welcome your comments and feedback!

We've received requests for .sha1 files in addition to .asc for our packages. Starting with 0.2.1.8-alpha, there are now .sha1 files in the appropriate dist directories. Displaying them on the download web page is still a bit tricky. The current layout leaves the page even more cluttered with .sha1 links all over it.

When you download a 0.2.1.8-alpha or later package, simply replace ".asc" with ".sha1" to get the hash file.

You'll then need to either "openssl sha1 {package}" or "sha1sum {package}" to see if the hash you downloaded matches the package you downloaded. Note: replace {package} with the name of the file you downloaded.

Enjoy.

If you don't know what any of this means, start here.

Aaron and Virgil's tor2web site has been picked up by Wired's 27bstroke6 blog and Ars Technica.

First off, I think it's a neat implementation of allowing non-Tor users access to the realm of .onion, aka hidden services. While I think using the Tor Browser Bundle is incredibly easy, not everyone agrees with me. Neither Tor nor tor2web host any of the hidden service content. We don't know who does, nor who runs the hidden service. This brings me to my next thought. read more »

Tor 0.2.1.8-alpha fixes some crash bugs in earlier alpha releases,
builds better on unusual platforms like Solaris and old OS X, and fixes
a variety of other issues.

https://www.torproject.org/download

Changes in version 0.2.1.8-alpha - 2008-12-08
Major features:

• New DirPortFrontPage option that takes an html file and publishes
  it as "/" on the DirPort. Now relay operators can provide a
  disclaimer without needing to set up a separate webserver. There's
  a sample disclaimer in contrib/tor-exit-notice.html.

Security fixes:

• When the client is choosing entry guards, now it selects at most
  one guard from a given relay family. Otherwise we could end up with
  all of our entry points into the network run by the same operator.
  Suggested by Camilo Viecco. Fix on 0.1.1.11-alpha.

Major bugfixes:

• Fix a DOS opportunity during the voting signature collection process
  at directory authorities. Spotted by rovv. Bugfix on 0.2.0.x.
• Fix a possible segfault when establishing an exit connection. Bugfix
  on 0.2.1.5-alpha.

Minor bugfixes: read more »

• Get file locking working on win32. Bugfix on 0.2.1.6-alpha. Fixes
  bug 859.
• Made Tor a little less aggressive about deleting expired
  certificates. Partial fix for bug 854.
• Stop doing unaligned memory access that generated bus errors on
  sparc64. Bugfix on 0.2.0.10-alpha. Fix for bug 862.
• Fix a crash bug when changing EntryNodes from the controller. Bugfix
  on 0.2.1.6-alpha. Fix for bug 867. Patched by Sebastian.
• Make USR2 log-level switch take effect immediately. Bugfix on
  0.1.2.8-beta.
• If one win32 nameserver fails to get added, continue adding the
  rest, and don't automatically fail.

Howcast produced a quick video for the masses on how to circumvent censorship. We were technical consultants for this video. It's tough to talk about Tor, when the first question you're trying to answer is "What is a proxy? And why do I care?"

Howcast did a great job for a high-level overview of circumvention technologies in four minutes.

As detailed here, http://archives.seul.org/or/talk/Dec-2008/msg00044.html, there are some packaging fixes for OS X users in this 0.2.0.32 stable release.

For OS X users, there is a packaging bugfix in 0.2.0.32 labelled as
0.2.0.32a in the available packages. It turns out for years we've been
shipping a Info.plist with an incorrect key. The issue was discovered
and reported as bug 876,
https://bugs.torproject.org/flyspray/index.php?id=876&do=details.

The commit to fix the problem in the 0_2_0 branch is r17472:
http://archives.seul.org/or/cvs/Dec-2008/msg00037.html

The commit to fix the problem in the Vidalia 0.1 branch is r3361:
http://trac.vidalia-project.net/browser/vidalia/branches/vidalia-0.1/pkg...

The bug is that the OS X Installer will prompt "The chosen volume
contains software which is newer then [sic] the software you are
installing."

The problem is that the Installer looks in the file
/Library/Receipts/Vidalia.pkg/Contents/Info.plist for
CFBundleShortVersionString. We mistakenly called it
CFBundleSortVersionString, which Apple inserts "1" as the value. The
upgrade to Vidalia from 0.1.9 to 0.1.10 apparently triggered the issue.

The fix is to put the correct value in place for the future. The
simplest way to do this is to have the users click "Continue" when
prompted. We could have spent a lot of time trying to fix it for the
user to hide the issue, but well, that is fraught with problems and
complexities. A simple click of "Continue" is far simpler and less
error prone.

The difference between the released 0.2.0.32 Tor code is the inclusion
of r17472. It's not really 0.2.0.32a per se, but since we lack package
versions, I had to distinguish it in some way.