[tor-talk] Fwd: [Full-disclosure] tor vulnerabilities?

[Nick Mathewson]

On Sat, Jun 29, 2013 at 5:53 PM, Nick Mathewson <nickm at alum.mit.edu> wrote:
> On Sat, Jun 29, 2013 at 4:43 PM, Cool Hand Luke
> <coolhandluke at coolhandluke.org> wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA512
>>
>> the below text was posted to pastebin.com (see original e-mail to the
>> full-disclosure list at the end of this message).
>>
>>
>> - ----- BEGIN PASTEBIN -----
>> Tor LOL:
>>
>> directory authorities are the point of contact for clients to locate
>> relays/exit nodes/guard nodes/etc. This is determined by a consensus
>> document that goes through an elaborate process to ensure its integrity
>> and cause bad directory authorities to be identified also via consensus.
>>
>> However, Tor developers are not the quickest lot, and this is basically
>> the only document that they serve that has integrity control on it. Most
>> interestingly, the public keys for every other node in the network is
>> served without any form of signature or other form of integrity control.
>>
>> As such, a rogue directory authority, which anyone can be simply with a
>> configuration option and an IP, can introduce path bias and other such
>> tricks by serving the wrong keys for relays/guards/exits that it doesnt
>> control. This can result in essentially directing clients through the
>> network by causing decryption failures, thereby allowing determination
>> of the source and end-point of a given tor connection with little more
>> than a couple relays and some rogue directory authorities. Moreover, it
>> can use the simple-minded metrics made to identify rogue guard nodes and
>> couple that together with the behavior of public key cryptography to
>> actually cause legitimate guard nodes to be flagged as having excessive
>> extend cell failures causing it ultimately to be marked as bad.
>
> I think this guy is confused.  I tried to tell him as much when he
> twittered at me last night; you can see more or less the full record
> if you look at the @nickm_tors from last night.

If you think he's actually got a point and you don't want to navigate
twitter's horrible search to find it , he started out tweeting as:
https://twitter.com/ewrwerwtretetet
then as https://twitter.com/ewrwerertertert
and then as https://twitter.com/ewrwerewrterter
and then as https://twitter.com/ewrwerewrterter
and finally as https://twitter.com/erertoiokoioiul

Like I said, I'm pretty sure that the stuff he's describing is simply
wrong.  Please feel free to check my work on this one though.

best wishes,
-- 
Nick