Re: blind demodulation - sound card - lucent winmodem - new topics

From: Evrim ULU (evrim@envy.com.tr)
Date: Sat Jul 06 2002 - 04:31:26 EDT


Jay Stapleton wrote:
> -----Original Message-----
> From: CJ Oster [mailto:cjo@dothe12.com]
> Sent: Thursday, July 04, 2002 10:51 PM
> To: Jay Stapleton
> Subject: Re: blind demodulation - sound card - lucent winmodem - new
> topics
>
> This idea is great, but you have to have access to the phone line to
> make it
> worth while, which means sitting at the telco distribution box on the
> corner
> of the person/place you want to sniff. While we're on the subject, does
> anybody know if a similar thing can be pulled off with a cable modem?
> They
> say cable modems are "shared media" which is why you never get the
> advertised speeds, but by "shared media", do they mean that every other
> user's signals are available on your cable line also? Just a thought.

Heh. Yes. Physical access is required but this is simple via slam boxes. (slam?
the boxes near the road which contains all lines to near houses. I do not
remember if they were called slam or so.) If one can demodulate the traffic, an
RF trasmitter can be placed inside these slams to sniff the line. Besides line
voltage can be used to fed these transmitters. We know that feeding something
from line voltage will decrease the quality of the line so we fed the line with
  neighbours' line. Since our neighbour is very old and does not have a
computer, she never realizes the decrease in the line voltage. Using the small &
dirty RF transmitter, a laptop inside a car can read the traffic while passing
near by the slam accidentally.

But of course these are spyware craps. Can be done but theory & idea of trellis
coded demod. is more important to me than the spyware RF implementation.

About cable modems, a friend told me that if somebody has a cable access in my
building than i can have access to internet simply by plugging the modem into my
coaxial cable. Of course, assuming providers' tftpd,dhcpd is buggy & can be
exploited. But i don't think that one can sniff neighbours traffic by this method.

-- 
Evrim ULU
evrim@envy.com.tr / evrim@core.gen.tr
sysadm
http://www.core.gen.tr
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