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RE: [Ecrit] Emergency Context Routing ofInternetTechnologies-Architectur

Subject: RE: [Ecrit] Emergency Context Routing ofInternetTechnologies-Architecture Considerations
From: "Winterbottom, James"
Date: Thu, 8 Sep 2005 18:36:18 -0500
Hi Ted,

My assumption would be that a large gateway box that services 20 or 100
PSAPs will require any attacker to mass several orders of magnitude more
zombies to launch a successful attack, than they would require to attack
a single PSAP. Maybe this is easy, I don't know, but it does up the anti

All this aside, I think that there are economies of scale, and
functionality reasons why including a gateway such an ESRP are
desirable, but these are more implementation details. Somewhere,
something has to have sufficient knowledge to use location to route the
signal to the next hop.


> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Ted Hardie
> Sent: Friday, 9 September 2005 3:55 AM
> To: [email protected]; [email protected]; Andrew Newton;
> Richard; ECRIT
> Subject: RE: [Ecrit] Emergency Context Routing ofInternetTechnologies-
> Architecture Considerations
> After reading the thread, I wanted to come back to Nate's original
> and call something out:
> >Here is the PSAP concern:
> >
> >An enterprising thief could figure out that a business (without an
> >system) in Backwater, Vermont is served by a PSAP located 25 miles
> >If one creates an IP-based denial of service attack on that PSAP then
> >is safe to assume that the target of opportunity that the thief is
> >looking at in Backwater will not be able to contact the PSAP to
> >help.
> I'm assuming that the PSAP being 25 miles away means nothing about
> where the responders are.  The responders in this instance might be
> sheriffs, for example, who are stationed nearby, even further than 25
> miles away, or whose patrol routes mean that their distance from the
> target of opportunity is variable.  So I think we should cut the
> from this description completely, and simply see the threat as "If the
> bad actor can determine which PSAP serves an area in which a target
> is present, a successful attack on the PSAP prevents responses to the
> target".
> Does that make sense?
> > Using PSTN technologies, an enterprising thief could create a PSTN
> >DoS on the PSAP by simply using an auto call generator from a pay
> >located in the same proximity as the target of opportunity however,
> >would still create a response to the general area of the crime.
> There are lots of other kinds of PSTN attacks here--the most commonly
> portrayed being "cutting the line", which doesn't work quite
> as it seems in the movies, but does have some effect.
> To avoid the locality problem in this attack, the bad actor can use an
> accomplice,
> meat or mechanical, in any other area served by the PSAP to do the
> same thing.  This avoids the response hitting the general area of
> the crime.  It also has the same counter-measure; call-blocking of the
> attacking phone.  This counter-measure is  also relatively easy to
> accomplish
> with an IP-based service, provided the attack is coming from a single
> IP or block. I believe the problem is harder in the IP case not
> the area
> from which the attack can originate is larger but because it is easier
> create a
> Distributed Denial of Service, largely because of zombie networks and
> spoofing.
> That is, if the attack is coming from Europe while the attack is
> on
> Backwater, my response is the same as if it came from Nearwater, VT:
> block the attack source.  But if it is coming from Europe, Asia,
> Nearwater,
> Backwater, and many other points as well, attempts to block the attack
> either requires effectively severing connectivity or maintaining a
> amount of information about who at the IP layer should be talking to
> this PSAP.  We've discussed the effectiveness of that in the past.
> >If I
> >know the URI of the PSAP, I can now distract it from another
> >and do what I would need to do in Backwater and no response would be
> >created in that direction - that is the new paradigm with IP. If I
> >the boundaries of the Derby PSAP, I could create a PSTN based DoS
> >anywhere from within that boundary (potentially 50 miles from Island
> >Pond).
> >
> >Would this happen? I don't know - I am pretty sure it hasn't yet but
> >assigning a URI to a PSAP opens it up to whole new generation of
> >"creative thinkers".....
> >
> >Of course we can minimize the impact on the PSAP at a higher level
> >gateway by throwing a huge amount of bandwidth at it and building in
> >intelligent alternative routing on a robust firewall. But that does
> >help in the interim between here and there when someone gets their
> >on the PSAP boundaries and realizes the attacks they can initiate
> >the PSTN DoS approach.
> The problem with the proposed solution, I believe, is that aggregating
> the access to a back-to-back user agent or all-knowing gateway
> is that you have simply created a richer target for attack.  If I can
> marshal
> a zombie group that takes out all of Vermont's PSAPs by eliminating
> the gateway by DDoS, I have done far worse far more easily than I
> by individually attacking the PSAPs at their URIs.  If I did it in
> to
> get at Backwater's target, I likely don't care that the general effect
> is larger--my purpose is met.
> Yes, it is easier to escalate the defenses at a single point and yes,
> is easier to
> pay for  fat pipes for that single point.  But the bad actors here
> using their
> own resources to attack you; they are stealing them before trying to
> steal from you.  Getting into an arms race with someone who isn't
> spending their own money worries me.
>                       regards,
>                               Ted
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