nanog mailing list archives

Re: Vulnerbilities of Interconnection


From: <sgorman1 () gmu edu>
Date: Thu, 05 Sep 2002 15:55:26 -0400


The question is what if someone was gunning for your fiber.  To date 
cuts have been unintentional.  Obviously the risk level is much higher 
doing a phyisical attack, but the bad guys in this scenario are not 
teenage hackers in the parents basement.  

There is a good foundation of knowledge on the implications of cyber 
attacks, but the what-if of an intentional physical attack is an 
important question I believe.  The context in this discussion has been 
very valuable and many thanks to everyone that has offered opinions.

----- Original Message -----
From: Dave Israel <davei () algx net>
Date: Thursday, September 5, 2002 3:50 pm
Subject: Re: Vulnerbilities of Interconnection


The thing is, the major cuts are not "attacks;" the backhoe operators
aren't gunning for our fiber (no matter how much it seems like they
are).  If I wanted to disrupt traffic, intentionally and maliciously,
I would not derail a train into a fiber path.  Doing so would be very
difficult, and the legal ramifications (murder, destruction of
property, etc, etc) are quite clear and severe.  However, if I
ping-bomb you from a thousand "0wn3d" PCs on cable modems, I never 
had
to leave my parents' basement, I'm harder to trace by normal police
methods, and the question of which laws that can be applied to me is
less clear. 

-Dave

On 9/5/2002 at 15:38:56 -0400, sgorman1 () gmu edu said:

"Again, it seems more likely and more technically effective to 
attack 
internally than physically. Focus again here on the cost/benefit 
analysis from both the provider and disrupter perspective and 
you will 
see what I mean."

Is there a general consensus that cyber/internal attacks are 
more 
effective/dangerous than physical attacks.  Anecdotally it seems 
the 
largest Internet downages have been from physical cuts or failures.

2001 Baltimore train tunnel vs. code red worm (see keynote report)
1999 Mclean fiber cut - cement truck
AT&T cascading switch failure
Utah fiber cut (date??)
Not sure where the MAI mess up at MAE east falls
Utah fiber cut (date??)

Then again this is the biased perspetive of the facet I'm 
researching> 
Secondly it seems that problems arise from physical cuts not 
because 
of a lack of redundant paths but a bottlneck in peering and 
transit -  
resulting in ripple effects seen with the Baltimore incident.



----- Original Message -----
From: "William B. Norton" <wbn () equinix com>
Date: Thursday, September 5, 2002 3:04 pm
Subject: Re: Vulnerbilities of Interconnection


At 02:45 PM 9/5/2002 -0400, alex () yuriev com wrote:
This obviously would be a thesis of Equinix and other collo 
space 
providers,>since this is exactly the service that they 
provide. It 
won't, hower, be a
thesis of any major network that either already has a lot of 
infrastructure>in place or has to be a network that is 
supposed to 
survive a physical
attack.

Actually, the underlying assumption of this paper is that 
major 
networks 
already have a large global backbone that need to interconnect 
in 
n-regions. The choice between Direct Circuits and Colo-based 
cross 
connects 
is discussed and documented with costs and tradeoffs. 
Surviving a 
major 
attack was not the focus of the paper...but...

When I did this research I asked ISPs how many Exchange Points 
they felt 
were needed in a region. Many said one was sufficient, that 
they 
were 
resilient across multiple exchange points and transit 
relationships, and 
preferred to engineer their own diversity separate from 
regional 
exchanges. 
A bunch said that two was the right number, each with 
different 
operating 
procedures, geographic locations, providers of fiber, etc. , 
as 
different 
as possible. Folks seemed unanimous about there not being more 
than two 
IXes in a region, that to do so would splinter the peering 
population.

Bill Woodcock was the exception to this last claim, positing 
(paraphrasing) 
that peering is an local routing optimization and that many 
inexpensive 
(relatively insecured) IXes are acceptable. The loss of any 
one 
simply 
removes the local  routing optimization and that transit is 
always 
an 
alternative for that traffic.


A couple physical security considerations came out of that 
research:> > 1) Consider that man holes are not always 
secured, 
providing access to
metro fiber runs, while there is generally greater 
security 
within
colocation environments

This is all great, except that the same metro fiber runs are 
used 
to get
carriers into the super-secure facility, and, since neither 
those 
who
originate information, nor those who ultimately consume the 
information are
located completely within facility, you still have the same 
problem.  If we
add to it that the diverse fibers tend to aggregate in the 
basement of the
building that houses the facility, multiple carriers use the 
same 
manholes>for their diverse fiber and so on.

Fine - we both agree that no transport provider is entirely 
protected from 
physical tampering if its fiber travels through insecure 
passageways. Note 
that some transport capacity into an IX doesn't necessarily 
travel 
along 
the same path as the metro providers, particularly those IXes 
located 
outside a metro region. There are also a multitude of paths, 
proportional 
to the # of providers still around in the metro area, that 
provide 
alternative paths into the IX. Within an IX therefore is a 
concentration of 
alternative providers,  and these alternative providers can be 
used as 
needed in the event of a path cut.


2) It is faster to repair physical disruptions at fewer 
points, leveraging
cutovers to alternative providers present in the 
collocation 
IX model, as
opposed to the Direct Circuit model where provisioning 
additional> > > > capacities to many end points may take days or 
months.> > >
This again is great in theory, unless you are talking about 
someone who
is planning on taking out the IX not accidently, but 
deliberately. To
illustrate this, one just needs to recall the infamous fiber 
cut 
in McLean
in 1999 when a backhoe not just cut Worldcom and Level(3) 
circuits, but
somehow let a cement truck to pour cement into Verizon's 
manhole 
that was
used by Level(3) and Worldcom.

Terrorists in cement trucks?

Again, it seems more likely and more technically effective to 
attack 
internally than physically. Focus again here on the 
cost/benefit 
analysis 
from both the provider and disrupter perspective and you will 
see 
what I mean.


Alex





-- 
Dave Israel
Senior Manager, DNE SE




Current thread: