Spitballing IoT Security

Ronald F. Guilmette rfg at tristatelogic.com
Mon Oct 24 20:24:59 UTC 2016

In message <e364fcea-7105-b3b9-63a9-7d22ab83516c at nuclearfallout.net>, 
John Weekes <jw at nuclearfallout.net> wrote:

>On 10/23/2016 4:19 PM, Ronald F. Guilmette wrote:
jw>>> ... The ISPs behind those IP addresses have
jw>>> received notifications via email...
rfg>> Just curious... How well is that working out?
>For the IoT botnets, most of the emails are ignored or rejected, because 
>most go to providers who either quietly bitbucket them or flat-out 
>reject all abuse emails. Most emails sent to mainland China, for 
>instance, are in that category (Hong Kong ISPs are somewhat better)...

So, given the apparently impracticality of trying to clean up all of these
kinds of messes via the good old-fashioned tedious and laborious method
of emailing the relevant providers and then just sort-of vaguely hoping
that they will -do something- responsible with it, I am just sitting here
trying to dream up some sort of generalized long-term fix for -all- of
these IoT DDoS type problems.

Maybe there just plain isn't any such thing as a general solution to the
problem, because it may perhaps be just technically too complex.  But I hope
no one will begrudge me if I yearn for some sort of Grand Unified Field
Theory of IoT security.

So, I have a thought... probably worth what you paid for it... and I'm just
brave enough to throw it out on the table and then everybody can pile on
and tell me what an idiot I am, for this or that perfectly sound technical
reason.  (I'll say up front that I don't even pretend to understand many
of the protocols in use these days, in particular UPnP, and to be frank,
I'd never even heard of SSDP until yesterday.  So I can't and won't begrudge
anybody who tells me that I have my head up... ummm... in the clouds.)

So anyway, here are the assumptions/assertions, perhaps wrong, which are my
starting point:

    1)  I am not persuaded that IoT devices have a compelling need to them-
        selves initiate outbound TCP sessions, ever.  (If I'm wrong about
        this, then I'm sure people here will tell me.)

    2)  Likewise, I am not persuaded that IoT devices have an absolute and
        compelling need to do very much in the way of UDP.  Yes, I would
        like my smart XYZ device to always know what time it is, so, you
        know, a modest amount of NTP traffic is reasonable and to be expected.
        Other than that however, I don't see a compelling need.  If you want
        to either control or get data out of your IoT device, you can make
        an inbound TCP connection to it.

        (Somebody will probably say "Oh, no.  We need to stream real-time
        video out of some of these things, and for that we absolutely have
        to send the stuff via outbound high-bandwidth UDP." but I am not
        persuaded that this is either absolutely necessary or even Good,
        i.e. from the point of view of the legitimate security concerns of
        the owner of the device.)

So, based on the above perhaps flawed assumptions, here is my idea.  It is
composed of two simple parts:

   1)  First, I will successfully complete my campaign to be elected King
       of the World.  (Given the current poltical climate, worldwide, this
       should not be a problem, because I lie a lot.)

   2) Second, once elected I will decree that in future all new IoT devices,
      and also all updates to firmware for existing IoT devices will have,
      BUILT IN TO THE KERNEL, code/logic which (a) prevents all outbound TCP
      session initiation and which also (b) strictly rate-limits all other
      protocols to some modest value.

Remember, we're going to have a few billion of these devices online in the
coming years.  If even and modest subset of these can ever be tricked by an
attacker into spewing non-rate-controlled traffic towards an attacker-
selected target, then we're gonna have a problem.


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