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Re: peculiar server "bandwidth" posted by server "mnl" and possible new type of attack

On Wed, Sep 10, 2008 at 7:28 AM, Scott Bennett <bennett@xxxxxxxxxx> wrote:
>>The fact of not being an exit node would make it a better corruped
>>relay? I mean, if I would like to DOS the Tor network I would be better
>     No, or at least I don't think so.  What I was referring to is that most
> of the trouble we've had from bad operators has taken the form of corrupted
> exit servers, where what goes into or comes out of the exit is in the clear
> and can be altered before it is sent where it is going.
>>to set the trojan node as internal?
>     For this kind of attack, I suppose there might be some sort of advantage
> to being only a relay and not an exit because route selection often prefers
> non-exit relays for non-exit positions in a route, and a typical route has
> two non-exit positions but only one exit position.  So the chances to bog
> down performance might be a bit higher if the attacker focused on non-exit
> usage.
>     But Roger has already said that clients believe that no server really
> handles more than 5 MB/s, so they trim any figures greater than that back to
> 5 MB/s.  If you had a dozen or two tor servers falsely reporting high usages,
> each at 5 MB/s or more, it might make a mess of things because they would
> distort the networkwide statistics, especially if those servers did not
> identify themselves as all being members of the same Family.

For reference, the reported bandwidth values from mnl hover around
2000 KB/s, but are very flaky (I'll assume this is caused by the
connection issues Domenico was talking about).



>                                  Scott Bennett, Comm. ASMELG, CFIAG
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> * Internet:       bennett at cs.niu.edu                              *
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Kasimir Gabert