Re: [PEN-TEST] OT - How secure is an ISDN line?

["van der Kooij, Hugo" <Hugo.van.der.Kooij () CAIW NL>]

On Fri, 20 Oct 2000, Cold Fire wrote:

> On Thu, Oct 19, 2000 at 03:38:40PM -0400, JLJ wrote:
> > ISDN is as secure as a phone call, no more or less.  If you can access the
> > wire anywhere along the route and have equipment you can snoop the line,
> > just like you can a phone call.  I don't really think it's sa,"Noo send much
> > of anything in the clear anymore...
>
> I have to disagree on this, while you can plug a phone (with a few
> simple adjustments, comenly called a beige box) into an analogue
> phone anywhere along the line and using either a linemans handset,
> or a datatap (available from the many exchange&mart spy shops in the
> uk). It was always my understanding that it was far more difficult
> to intercept a digital connection rather than a analogue connection
> that said, as long as they are using a 56k connection it sould be
> pretty difficult to intercept anyway, of course you could slow the
> connection down ( by way of line noise eiugh to force it into an
> much more intercept friendly mode of none error correcting 4800/9600.

ISDN is fundamentaly different from analog lines. There is no such thing
as 'slowing ISDN down'. However it isn't to difficult to create a wiretap.
The electronics are quite basic. Decoding ISDN owuld require some more
effort but if you don't have a generic sniffer you should be able to build
a listening only ISDN device.

As a matter of fact there are ISDN taps on the market. The purpose is to
analyze problems. However setting up a network tap for interception
purposes using one shouldn't be hard.

In most cases there are easier ways to access information but if you want
to and have a budget like the NSA you can tap literally everything (and
they tap a lot more then you would like to.)

Hugo.

--
Hugo van der Kooij; Oranje Nassaustraat 16; 3155 VJ  Maasland
hvdkooij () caiw nl     http://home.kabelfoon.nl/~hvdkooij/
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