[tor-talk] Tor DNS Deanonymization
phw at nymity.ch
Tue Oct 18 14:39:59 UTC 2016
On Sun, Oct 16, 2016 at 01:15:32AM -0400, Nick Mathewson wrote:
> On Fri, Oct 14, 2016 at 11:09 AM, Philipp Winter <phw at nymity.ch> wrote:
> > There are two ways to mitigate the issue. First, we need better
> > defences against website fingerprinting, so an attacker learns less by
> > observing the connection to your guard relay. Second, we need to
> > improve the DNS setup of exit relays. I would like to see less relays
> > use Google's resolver, and we need to move towards encrypted DNS.
> Thanks, Philipp!
> Could you comment at all about whether our current exit side dns
> caching approach makes the attack harder, easier, or doesn't matter?
Generally, the longer exit relays cache domains, the less precise the
attack. The trade-off is illustrated in Figure 10b in our paper .
At the moment, exit relays cache domains for only 60 seconds ,
regardless of the domain's TTL. If that bug is fixed, the attack
becomes a bit harder to mount. It can become even harder if exit relays
were to cache each domain for, say, 10 minutes or more.
More information about the tor-talk