On Mon, Mar 10, 2014 at 3:43 PM, Owen DeLong <[email protected]> wrote:

>
> Can you give me an example of what would be the scenario here?  Assuming I
> am the upstream ISP of the "hosts I control, willing to subject them to
> vast quantities of traffic".  Would I announce 1.2.3.0/24 upstream, and
> point it to my customer's link?
>
>
> I'm not assuming that the upstream ISP would be the malefactor. That is,
> in fact, a rather odd assumption, is it not?
>

Very odd, but I was trying to think of ways to force someone to use my
servers.


> OTOH, if you are a malefactor that wants to turn your botnet into
> anycasted DNS servers to issue incorrect redirections to others, getting
> said botnet (or its upstream routers if you are able to control them
> somehow) to announce 1.2.3.0/24 really doesn't pose any problem to you as
> a result of the traffic it generates.
>

This is the part that I really do not understand.  Suppose I control a
significant number of Windows7 PCs, and a few Cisco Routers, in your
network, through a C&C botnet.  How would I get them (the PCs) to make
announcements for 1.2.3.0/24?  I could install quagga (after porting it)
quietly on them, but who would the Windows 7 PCs peer with?  Only the
routers under my control?  In which case, what would be the point?

I could get the Ciscos to startup BGP, and start announcing 1.2.3.0/24 ,
but to whom?  Again, I can only peer if I control both sides of the link,
and if I control both sides, why do anycast anywhay?  I have control on the
RIB.

If I controlled the Routers at the edge of your network, I could redirect
traffic from your nodes to any address I wished.  This requires no new DNS,
or 1.2.3.0/24 routing.

There is one other case I can think of.  Start DNS servers on the zombie
PCs, assign them 1.2.3.4, and use them as a DNS server farm.  But who would
come to them?  If this was a home network (or any kind of leaf network),
assigning 8.8.8.8 to my interface does not make you next to me send your
DNS query to me.


>
> Or would I announce 1.2.3.0/24 from another ISP's origin AS?
>
>
> Not sure how that would work or help other than in an attempt to cover
> your tracks.
>

Thank you, so we can close that scenario I postulated as invalid.


> How would (evil me) be able to hurt hosts other than on _my_ network?
>
>
> You are assuming that you are doing this with routers you own (in the
> commercial sense of the word). I am assuming someone doing this with
> routers that they control (in the enable access sense of the word) but do
> not own (in the commercial sense of the word).
>
> Malefactors these days are rather well known for using other people's
> equipment to carry out their misdeeds, or are you unfamiliar with the term
> "botnet"?
>

I am aware of the concept, and some implementations.  And I appreciate your
distinction between the the "own" and "control" part, it helps bisect the
problem.

Suppose I subvert a router in your network (might be your edge router,
might be an internal).  Now what?  Where does 1.2.3.0/24 come into the
picture?


> I am not doubting that people would not want to misuse this, but how would
> this work in the case you have outlined?
>
>
> I hope I have adequately clarified.


I can understand if I am being too slow in picking up something obvious.  I
am still nt seeing a _new_ attack vector _due_ to 1.2.3.0/24 being allowed
to be used internally (and even leaking externally).


-- 
Sanjeev Gupta
+65 98551208   http://sg.linkedin.com/in/ghane
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