[Bitcoin-development] Abnormally Large Tor node accepting only Bitcoin traffic

Anatole Shaw btcsf at omni.poc.net
Mon Jul 28 03:12:35 UTC 2014


It's not quite accurate that the Tor node's throughput is 'mostly'
plaintext Bitcoin traffic. The node will only exit bitcoin traffic (or
anything else on port 8333) but most of the bandwidth is probably used
in being a Tor relay where there can be no port number discrimination.

However by providing so much bandwidth to the Tor network (maybe
record-setting?) and providing exit service for 8333, the node puts
itself in a strong position to do any or all of the following:

(a) Observe a lot of Bitcoin traffic from users connecting with Tor.

(b) Tamper with said traffic in some way.

(c) Hide the administrator's self-generated Bitcoin traffic in a crowd
of other Bitcoin traffic emitting from the same IP address.

Any of those possibilties might be intriguing.

Anatole


On Sun, Jul 27, 2014 at 10:17:19PM -0400, Jeremy wrote:
> Credit to Anatole Shaw for discovering.
> 
> 
> On Sun, Jul 27, 2014 at 10:12 PM, Jeremy <jlrubin at mit.edu> wrote:
> 
> > Hey,
> >
> > There is a potential network exploit going on. In the last three days, a
> > node (unnamed) came online and is now processing the most traffic out of
> > any tor node -- and it is mostly plaintext Bitcoin traffic.
> >
> >
> > http://torstatus.blutmagie.de/router_detail.php?FP=0d6d2caafbb32ba85ee5162395f610ae42930124
> >
> > Alex Stamos (cc'ed) and I have been discussing on twitter what this could
> > mean, wanted to raise it to the attention of this group for discussion.
> >
> > What we know so far:
> >
> > - Only port 8333 is open
> > - The node has been up for 3 days, and is doing a lot of bandwidth, mostly
> > plaintext Bitcoin traffic
> > - This is probably pretty expensive to run? Alex suggests that the most
> > expensive server at the company hosting is 299€/mo with 50TB of traffic
> >
> >
> > --
> > Jeremy Rubin
> >
> 
> 
> 
> -- 
> Jeremy Rubin





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