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Privacy Security Upgrades

Tor Users Urged To Update After Security Breach 161

Posted by timothy
from the points-of-failure dept.
An anonymous reader writes "If you use Tor, you're cautioned to update now due to a security breach. In a message on the Tor mailing list dated Jan 20, 2010, Tor developer Roger Dingledine outlines the issue and why you should upgrade to Tor 0.2.1.22 or 0.2.2.7-alpha now: '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.' Tor users should visit the download page and update ASAP."
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Tor Users Urged To Update After Security Breach

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  • by Anonymous Coward on Thursday January 21, 2010 @11:08PM (#30855820)

    Roger's entries to date on the subject (excluding first page linked within /. summary):

    (this is for those who are too lazy to page through mailing list threads, this post is
    missing other individuals replies as well as future replies from Roger and others)

    http://archives.seul.org/or/talk/Jan-2010/msg00165.html [seul.org]

    Here are some more technical details about the potential impacts, for
    those who want to know more about Tor's innards:

    ----- #1: Directory authority keys

    Owning two out of seven directory authorities isn't enough to make a new
    networkstatus consensus (you need four for that), but it means you've
    only got two more to go. We've generated new v3 long-term identity keys
    for these two authorities.

    The old v3 long-term identity keys probably aren't compromised, since
    they weren't stored on the affected machines, but they signed v3 signing
    keys that are valid until 2010-04-12 in the case of moria1 and until
    2010-05-04 in the case of gabelmoo. That's still a pretty big window,
    so it's best to upgrade clients away from trusting those keys.

    You should upgrade to 0.2.1.22 or 0.2.2.7-alpha, which uses the new v3
    long-term identity keys (with a new set of signing keys).

    ----- #2: Relay identity keys

    We already have a way to cleanly migrate to a new v3 long-term identity
    key, because we needed one for the Debian weak RNG bug:
    http://archives.seul.org/or/announce/May-2008/msg00000.html [seul.org]

    But we don't have a way to cleanly migrate relay identity keys. An
    attacker who knows moria1's relay identity key can craft a new descriptor
    for it with a new onion key (or even a new IP address), and then
    man-in-the-middle traffic coming to the relay. They wouldn't be able to
    spoof directory statements, or break the encryption for further relays
    in the path, but it still removes one layer of the defense-in-depth.

    Normally there's nothing special about the relay identity key (if you
    lose yours, just generate another one), but relay identity keys for
    directory authorities are hard-coded in the Tor bundle so the client
    can detect man-in-the-middle attacks on bootstrapping.

    So we abandoned the old relay identity keys too. That means abandoning
    the old IP:port the authorities were listening on, or older clients will
    produce warn messages whenever they connect to the new authority. Older
    Tor clients can now take longer to bootstrap if they try the abandoned
    addresses first. (You should upgrade.)

    ----- #3: Infrastructure services

    Moria also hosted our git repository and svn repository. I took the
    services offline as soon as we learned of the breach -- in theory a clever
    attacker could give out altered files to people who check out the source,
    or even tailor his answers based on who's doing the git update. We're
    in pretty good shape for git though: the git tree is a set of hashes
    all the way back to the root, so when you update your git tree, it will
    automatically notice any tampering.

    As explained in the last mail, it appears the attackers didn't realize
    what they broke into. We had already been slowly migrating Tor services
    off of moria (it runs too many services for too many different projects),
    so we took this opportunity to speed up that plan. A friendly anonymous
    sponsor has provided a pile of new servers, and git and svn are now up
    in their new locations. The only remaining Tor infrastructure services on
    moria are the directory authority, the mailing lists, and a DNS secondary.

    ----- #4: Bridge descriptors

    The metrics server had an archive of bridge descriptors from 2009.
    We used the descriptors to create summary graphs of bridge count and
    bridge usage by country, like the ones you can see at
    http://metrics.torproject. [torproject.org]

  • Re:Tor weaknesses (Score:5, Informative)

    by v1 (525388) on Thursday January 21, 2010 @11:11PM (#30855866) Homepage Journal

    They don't even use encryption and

    Oh but they do, and that's the key to the problem. Everyone and their dog knows where the C&C servers are, and can monitor the commands sent out. Problem is, the commands are cryptographically signed, usually with a hideously large key (last one I saw was 2048 BYTES) so you can't subvert their network. Improperly signed commands are merely ignored.

    The bot herders get their anonymity from any of a hundred ways to anonymously sign into the IRC C&C channel. I'd speculate that most of them use TOR to do so.

  • Re:Sooo...... (Score:1, Informative)

    by Anonymous Coward on Thursday January 21, 2010 @11:33PM (#30855992)
    I love it when clueless people comment and show their ignorance, it's good for future reference.

    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.

    * Does this mean someone could have matched users up to their destinations?
    No....

    * 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...

  • Re:Sooo...... (Score:3, Informative)

    by Anonymous Coward on Thursday January 21, 2010 @11:39PM (#30856026)

    I spent a bit over a year working with the FBI gathering information on a pedophile ring who was using one of our servers (to coordinate picture trading going on in Asian image board sites). Neither agents' opinions, the content gathered, nor the actual research I've seen, agree with your unsupported assertion that "they are one and the same". Though, two troll paratrooper points for accusing those who disagree with you of naivete. Good show, golf claps all around.

    I also don't know to what extent the "pedo" content in actual prepubescent kids, versus underage pubescent ("jailbait"). No, I don't really want to know either. Anyway, ephibophilia is illegal, but arguably medically normal, and ephibophiles and pedophiles make up separate populations.

  • Re:Sooo...... (Score:5, Informative)

    by clang_jangle (975789) on Friday January 22, 2010 @12:33AM (#30856344) Journal

    But until it's as simple as hitting a button in Firefox to use Tor, of course it's only going to be the enthusiasts and scumbag fringes that'll put the time into researching and securing their privacy online.

    Duh! [mozilla.org]

  • Re:Sooo...... (Score:3, Informative)

    by trytoguess (875793) on Friday January 22, 2010 @12:50AM (#30856432)

    This is somewhat tangential, but there is illustrated porn where just about any deviance can be catered to without harming a minor. Actually molesting a child is wrong of course.

  • Re:Sooo...... (Score:2, Informative)

    by larry bagina (561269) on Friday January 22, 2010 @01:32AM (#30856642) Journal
    tor also lets you run an (anonymous) file server.
  • by VortexCortex (1117377) <VortexCortexNO@S ... t-retrograde.com> on Friday January 22, 2010 @01:33AM (#30856644)

    Wait... Anyone can be a TOR node [torproject.org] and it's still secure.

    TOR data is very encrypted.

    It doesn't matter if the hardware or software is compromised, it's still secure because a TOR node is just one node in a chain of encrypted nodes. You encrypt your data 5 times if you're sending it through 5 nodes.

    Each node takes off one layer of encryption and forwards the still encrypted data to the next node. If any intermediate nodes (2 3 4 in our 5 node example) are compromised (in software or hardware), they can not see the message in plain text, or determine the originating IP or destination IP of the traffic.

    If the first node is compromised it can see your source IP, but not the destination IP or any part of the message (it's still encrypted.)

    If the exit node is compromised it can see the destination IP, and clear text message, but not the source IP.

    These multiple layers of encryption mean that if any one node is compromised the system is still very secure.

    Taking off a layer of encryption at each router is like peeling an onion... hence, "The Onion Router".

    (this is an oversimplified explanaion -- if you're talking compromised code repositories, viruses and trojans are usually not delivered as source code, the tampering would be evident.)

To err is human -- to blame it on a computer is even more so.

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