[Ndn-interest] Largest DDoS attack ever delivered by botnet of hijacked IoT devices

GTS gts at ics.uci.edu
Wed Sep 28 13:26:21 PDT 2016

To get back to the issue of having or not having the PIT:

Recall that this thread started with discussion of massive DoS attacks on
the current Internet, initiated from IoT devices. It progressed to a 
of DoS attacks in CCN. It was then suggested that a PIT-less
design might address the only glaring major type of DoS attack in CCN --
interest flooding. I specifically say "address", not "solve" or "obviate".
(That's because even a PIT-less design allows the producers to be 
Now, the particular PIT-less design that Cesar mentioned is this:


It is NOT motivated solely by interest flooding mitigation. It just happens
to be one of its features. The authors (of whom I'm one) would love to
hear some reasoned criticism of this PIT-less design. It should be based
on actually reading the paper.

More generally, the PIT is currently a fundamental feature of both NDN 
and CCNx.
Should it even be questioned? To some true believers, this is clearly an 
IMHO, all architecture features should be up for debate and all dogmas 
ought to be questioned.
For example, I believe that the PIT and the CACHE (for example) are not 
make an architecture Content-Centric. Either or both can be removed and 
remains would still be a Content-Centric Network (though perhaps not a 
good one).

Finally, the PIT-less design mentioned above could well be ill-advised,
or even totally senseless. We simply don't know yet.
Indeed, as the paper admits, it has some problems of its own.
Or, it might make sense in some settings, e.g., where the
network infrastructure is mobile. Or, it might be an 
alternative/optional implementation.
(BTW, it can in fact co-exist with a PIT-ful CCN).


Gene Tsudik
Chancellor's Professor of Computer Science
University of California, Irvine

On 9/27/16 10:12 PM, Luca Muscariello wrote:
> The work JJ has presented this morning is probably another interesting 
> thread.
> And I agree that the signal mentioned here is not a prerogative of the 
> PIT.
> So, to stay in topic to this thread, from my point of you what JJ has 
> proposed
> has more compelling properties to remove the PIT than the DDoS example
> considered here.
> In JJ's proposition, you trade something for something else. It's not 
> an equivalent
> architecture to NDN though. So we need to be careful before laying 
> away pieces of the architecture. There is a  price for that.
> On Wednesday, 28 September 2016, <Marc.Mosko at parc.com 
> <mailto:Marc.Mosko at parc.com>> wrote:
>     Removing the PIT and using, for example, a label swapping approach
>     such as J.J. Garcia-Luna-Aceves has suggested, does not remove the
>     “signal” you talk about.  One could keep upstream and downstream
>     counters for each label swap identifier and see which labels are
>     not getting downstream data.
>     I do not think the strategy of purging PIT entries based on the
>     shortness of their remaining lifetime gives you any correlation to
>     purging attack packets.  First of all, an attacker could easily
>     use a very large Interest Lifetime. Well-behaved clients that are
>     using RTT estimates in their Interest Lifetime would, by
>     definition, likely have very small margins in the Interest
>     Lifetime remaining  before the Data comes back (personally, I
>     think it is a problem to make InterestLifetime based on RTT, but
>     that’s a different thread).
>     Marc
>     > On Sep 28, 2016, at 10:47 AM, christopherwood07 at gmail.com wrote:
>     >
>     > On September 27, 2016 at 5:14:14 PM, Christos Papadopoulos
>     > (christos at colostate.edu) wrote:
>     >>
>     >>
>     >> On 09/27/2016 04:59 PM, woodc1 at uci.edu wrote:
>     >>> To re-iterate Cesar’s point, as of now, there is no truly
>     effective
>     >>> interest flooding mitigation. However, one concrete way to
>     minimize
>     >>> the attack surface (for routers) is to get rid of the attack's
>     root
>     >>> cause: the PIT. (Producers could still be hosed with bogus
>     interests.)
>     >>> And since the PIT enables several important functions, other
>     >>> architecture changes will probably have to follow in its wake.
>     >>
>     >> You start with what I believe to be the wrong premise:
>     protecting the
>     >> router. In NDN we care about communication, not a single router.
>     >> Protecting a router is winning the battle but losing the war.
>     >
>     > I respectfully disagree. If the adversary takes out the producer,
>     > there is no communication. If the adversary takes out the routers
>     > adjacent or otherwise on the path to the producer, there is no
>     > communication. Protecting the router(s) is equally important,
>     > especially since it may impact more than just a single producer.
>     >
>     >>
>     >> I don't understand your statement that the root cause of DDoS
>     attacks is
>     >> the PIT. The root cause of DDoS is resource exhaustion.
>     >
>     > In these attack scenarios, the PIT *is* the resource being
>     exhausted.
>     >
>     >>
>     >>>
>     >>> Personally, I don’t think we should settle with an architectural
>     >>> element that has a known (and quite severe) weakness simply
>     because it
>     >>> enables some nice features in practice. The more serious design
>     >>> problems must be dealt with first, not last.
>     >>
>     >> You are underestimating the importance of the signal the PIT
>     provides.
>     >> It is an important insight into the status of communication.
>     The PIT
>     >> does not simply enable some "nice features". Think a bit harder
>     about
>     >> the things you can do with this signal.
>     >
>     > In most attack scenarios, yes, it tells you when bogus interests are
>     > flooding a particular prefix and otherwise when communication is
>     > failing. But consider this scenario. Suppose you have a malicious
>     > producer cooperating with one or more malicious consumers. The
>     > consumers are quickly sending interests to this legitimate producer,
>     > who responds with legitimate data. The communication is not failing.
>     > Their goal is to do nothing other than saturate the PIT of some
>     > intermediate router. Per Spyros’ follow-up suggestion, that router
>     > might kick out old, legitimate interests in favor of these malicious
>     > ones. Of course, this is fundamentally how we would expect one
>     to deal
>     > with and manage a limited resource. So preventing this attack seems
>     > difficult for any approach. But the point is that this resource, the
>     > PIT, is easily abused in CCN/NDN.
>     >
>     > Chris
>     >
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