[tor-talk] Source code modifying for testing

[NGUYEN Quoc Viet]

Thanks Robert.
I know that there was several attacks with control of both exit and entry
node.
And I just want to test that attack and evaluate its effectiveness.
Regards.
2011/5/11 Robert Ransom <rransom.8774 at gmail.com>

> On Wed, 11 May 2011 10:11:07 +0200
> NGUYEN Quoc Viet <quocviet.pfiev at gmail.com> wrote:
>
> > I'm now researching an attack against Tor.
> >
> > *Resume of Attack*: We control exit node and entry node. Upon receiving a
> > RELAY BEGIN cell,the exit node will forger  a malicious webpage to
> client.
> > The webpage contains some empty gif files. The entry node will be able to
> > detect a distinctive pattern of the connection to that malicious webpage,
> > basing on number of relay cells backward and forward.
>
> If you can control both the entry and exit nodes, you don't even need
> to perform an active attack -- a purely passive timing attack will
> identify the client.  That's why each Tor client selects a few relays
> to use as ‘entry guards’ -- see
> <https://www.torproject.org/docs/faq#EntryGuards> and
> <http://freehaven.net/anonbib/#hs-attack06>.
>
>
> > For implementation, it's needed to modify a piece of Tor source code at
> the
> > exit node, to forger a malicious webpage to client. Notice that this is
> not
> > modifying webpage response from the server, but forger attacker's webpage
> to
> > the client. Could some one please give a hint about where I need to
> modify.
>
> No.
>
>
> Robert Ransom
>
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>


-- 
Nguyen Quoc Viet
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