nanog mailing list archives

Re: Vulnerbilities of Interconnection


From: "Pawlukiewicz Jane" <pawlukiewicz_jane () bah com>
Date: Fri, 06 Sep 2002 09:11:35 -0400


Hi,

sgorman1 () gmu edu wrote:

"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.

It depends on what you consider and internet outage. Or how you define
that. IMHO.

Jane

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





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