Tor Project infrastructure updates in response to security breach

[Roger Dingledine]

You should upgrade to Tor 0.2.1.22 or 0.2.2.7-alpha:
https://www.torproject.org/download.html.en

In early January we discovered that two of the seven directory
authorities were compromised (moria1 and gabelmoo), along with
metrics.torproject.org, a new server we'd recently set up to serve
metrics data and graphs. The three servers have since been reinstalled
with service migrated to other servers.

We made fresh identity keys for the two directory authorities, which is
why you need to upgrade.

Moria also hosted our git repository and svn repository. We took the
services offline as soon as we learned of the breach. It appears the
attackers didn't realize what they broke into -- just that they had
found some servers with lots of bandwidth. The attackers set up some ssh
keys and proceeded to use the three servers for launching other attacks.
We've done some preliminary comparisons, and it looks like git and svn
were not touched in any way.

We've been very lucky the past few years regarding security. It still
seems this breach is unrelated to Tor itself. To be clear, it doesn't
seem that anyone specifically attacked our servers to get at Tor. It
seems we were attacked for the cpu capacity and bandwidth of the servers,
and the servers just happened to also carry out functions for Tor.

We've tried to address the most common questions below.

* Does this mean someone could have matched users up to their
destinations?

No. By design, Tor requires a majority of directory authorities (four
in this case) to generate a consensus; and like other relays in the
Tor network, directory authorities don't know enough to match a user
and traffic or destination.

* Does this mean somebody could have changed the Tor source?

No, we've checked the source. It does mean you should upgrade so your
client knows about all the currently valid directory authorities.

* Does this mean someone could have learned more about Tor than an
ordinary user?

Since our software and specifications are open, everyone already has
access to almost everything on these machines... except some old bridge
descriptors, which we give out only in small batches as entry points for
blocked clients.

* Can I trust Tor's security?

We've taken steps to fix the weaknesses identified and to harden our
systems further. Tor has a track record of openness and transparency,
with its source code and specifications and also with its operations.
Moreover, we're disclosing breaches such as this so you can monitor our
status. You shouldn't assume those who don't disclose security breaches
never have any!

--Roger

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