Home page logo

isn logo Information Security News mailing list archives

From: InfoSec News <isn () c4i org>
Date: Mon, 1 Oct 2001 05:16:54 -0500 (CDT)

Forwarded from: Steven Hess <s_hess () msn com>

[This is the last posting on the E-Bomb thread.  -  WK]

Hash: SHA1

The technology looks like the same as for lightning protection. I
think the protection would be similar. 

Lightning does damage not only by striking the component electrical
path, but by generating the same kind of high strength EMP - the bolt
is comprised of several strokes, and each one generates EMF lines of
force. When these moving fields cut through a conductor, a (lower
voltage) is generated in the conductor, perhaps spikes of several
hundred volts or so. 

The current state of lighting protection is to :
1. shunt spikes to ground on conductors with MOSFET or similar
variable semiconductors. (you see a cheap version in a surge
supressed power strip)
2. ground chassis and cases to isolate from EMP and arcs. 
3. Signal isolation via fiber optic. 
4. Star Grounding system to prevent conductance between different
ground systems. (Racks should be grounded on a separate system from
AC electrical grounds, and should be bonded only at the
Ground/Neutral connection point).  

The "faraday cage" mentioned is the same as placing equipment in a
grounded case, with the exception that the cage has "holes" in it
that depending on frequency, offer a path for the cage to leak RF in.
The cage should work, though better than a grounded case if the
following is true - If the EMP pulse is very low frequency, and the
Faraday cage is made up of higher current carrying capability. We use
different kinds of grounding depending on what is to be shunted, four
ought cable for low frequency, copper flashing for high frequency. 

My experience is with Television Broadcast towers and transmitters,
and the associated broadcast equipment, which get hit with lightning
a lot. Most of the damaged systems are not struck directly, but
surged on their power, data, video, audio, or phone connections. A
UPS can help, if it incorporates surge supression, and it isolates
the power from the line. Phone line supressors work to a certain
extent, but nothing I have found keeps everything working all the
time - even the fiber optic units can sacrifice themselves on the
"outside" connection. 

Steven Hess
Assistant Chief Engineer
(lightning capital of the world - no kidding) 

-----Original Message-----
From: owner-isn () attrition org [mailto:owner-isn () attrition org]On
Behalf Of InfoSec News
Sent: Sunday, September 30, 2001 6:12 AM
To: isn () attrition org
Subject: Re: [ISN] E-BOMB 

Forwarded from: Darren Reed <darrenr () reed wattle id au>

In some email I received from InfoSec News, sie wrote:
Forwarded from: Russell Coker <russell () coker com au>

On Fri, 21 Sep 2001 09:39, you wrote:

September 2001

In the blink of an eye, electromagnetic bombs could throw
civilization back 200 years. And terrorists can build them for

This is a very interesting article, but it fails to mention one
crucial point.  What is the effect of an EMP weapon on magnetic

Somewhere in that article, it mentions "magnetic field", if I
recall correctly.  I don't remember enough physics to recall the
interfaction between faraday cages and magnetic fields (of what
strength even?).  

Elsewhere on this topic mention of faraday cages has been made.

On that topic someone said that isn't enough.  The most important
point is you _cannot_ have _any_ wires going in or out of that
faraday cage - it needs to be completely eletrically isolated.  No
data leads, no power leads going in or out of it that contain a
conductor.  For data, this is an easy problem: fibre.  100BaseFX,
ATM, GigE, FDDI come to mind.  But how do you fix the problem of
power?  Does anyone know of any mechanical (or other) means of
getting power into/out of a
faraday cage without there being any conductive path through ? 
Where do you go to buy such equipment (assuming it is unclassified)
?  Can you buy, for example, laser based power couplers ?  (power
in one
side, laser beam over 6 inces, power out the other side).

I'm almost 100% sure a UPS is not going to save you.  Their
reaction times are too slow for the rise generated by an E-Bomb and
even then some of them will switch out to save themselves and your
equipment goes "boom".


ISN is currently hosted by Attrition.org

To unsubscribe email majordomo () attrition org with 'unsubscribe 
isn' in the BODY
of the mail.

Version: PGP Personal Privacy 6.5.3


ISN is currently hosted by Attrition.org

To unsubscribe email majordomo () attrition org with 'unsubscribe isn' in the BODY
of the mail.

  By Date           By Thread  

Current thread:
  • RE: E-BOMB InfoSec News (Oct 01)
    • <Possible follow-ups>
    • Re: E-BOMB InfoSec News (Oct 05)
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]