nanog mailing list archives

Re: First real-world SCADA attack in US


From: Jay Ashworth <jra () baylink com>
Date: Mon, 21 Nov 2011 23:16:14 -0500 (EST)

----- Original Message -----
From: "Jimmy Hess" <mysidia () gmail com>

On Mon, Nov 21, 2011 at 3:35 PM, Mark Radabaugh <mark () amplex net>
wrote:
On 11/21/11 10:32 AM, Jay Ashworth wrote:
education / resource issue. The existing methods that have been used for
years with reasonable success in the IT industry can 'fix' this
problem.

Careful with the attribution; you're quoting Mark, not me.

The weakness of typical IT security is probably OK, when the only danger of compromise
is that an intruder might get some sensitive information, or IT might need to go to the tapes.

That just won't do, when the result of compromise is, industrial equipment
is forced outside
of safe parameters, resulting in deaths, or a city's water supply is shut down,
resulting in deaths.

(72 character hard wrap... please.)

Hard perimeter and mushy interior with OS updates just to address
known issues, and malware scanners to "try and catch" things just won't do.

Precisely.  THe case in point example these days is traffic light controllers.

I know from traffic light controllers; when I was a kid, that was my dad's
beat for the City of Boston.  Being a geeky kid, I drilled the guys in the
signal shop, the few times I got to go there (Saturdays, and such).

The old design for traffic signal controllers was that the relays that drove
each signal/group were electrically interlocked: the relay that made N/S able 
to engage it's greens *got its power from* the relay that made E/W red; if there
wasn't a red there, you *couldn't* make the other direction green.

These days, I'm not sure that's still true: I can *see* the signal change
propagate across a row of 5 LED signals from one end to the other.  Since I 
don't think the speed of electricity is slow enough to do that (it's probably 
on the order of 5ms light to light), I have to assume that it's processor delay
as the processor runs a display list to turn on output transistors that drive
the LED light heads.

That implies to me that it is *physically* possible to get opposing greens
(which we refer to, in technical terms as "traffic fatalities") out of the
controller box... in exactly the same way that it didn't used to be.

That's unsettling enough that I'm going to go hunt down a signal mechanic
and ask.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274


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