| From: | Anthony W. Prime |
| Date: | 19 Apr 2001 at 00:47:25 |
| Subject: | Re: Phone Hoax E-mail |
Hi Stephen. On Wed, 18 Apr 2001 you wrote:
>> You`re probably thinking about Cloning of the old ETACS standard (which
>> didn`t have sim cards). With simple equiptment you could pull the required
>> information out of the air and clone a handset to believe it was another,
>> because the handset ESN was sent as a burst of tones and could easily be
>> decoded. That was one of the reasons behind the move to the GSM standard.
>Correct. They were also very easily monitored by using a radio scanner.
Oh I know :)
The number of back to back calls I used to listen to that went something
along the lines of
1. Sorry Darling I`ve got to work late. Yes I know it`s a pain. See you
later, love you.
2. Hello Darling. Meet you in about half an hour. Can`t be too long though
I`ve got to travel to Brussels and be a the airport for a 2am check in
You get the picture. TACS switch off means I`ve had to start watching soap
operas :)
>> I`m sure Steven will give you a far more in depth answer than I (and
>> correct my errors), but gathering any information in this way from a GSM
>> network is virtually impossible as the handsets use encryption and
>> timeshare with each other to maximise bandwidth usage, and as mobile
>> phones are, urm, mobile, the timing of packets of data can vary within a
>> short time if the user is in a car or on a train.
>Yes and no. Yes the handsets use encryption, but the fact that they share
> (up to) 8 digital channels per frequency is merely better use of capacity.
> To clone a SIM card, you would need far more information than is sent over
> the air at once. For example, most people know about the MSISDN (Mobile
> Station Integrated Services Digital Network) or phone number. But equally
> important is your IMSI (International Mobile Subscriber Identity) which is
> only ever broadcast when you turn your phone on, and not at the same time
> as your MSISDN. thereafter, the network allocates you a TMSI, or Temporary
> mobile Subscriber Identity which is used instead of your IMSI, and changes
> periodically. You need MSISDN and IMSI, plus a few other things which I
> won't go into in case people start getting ideas (go read the ETSI specs if
> you are really desperate to know), and the MSISDN and IMSI are never sent
> together.
I seem to recall somewhere that you could clone a sim card, but you would
need to have the original (and destroy the original in the process), so
defeating the object?
>> Actually it amazes me that they connect at all. Oh wait a minute, one2one
>> handsets dont :0)
>No comment :-)
Then allow me to comment for you. [Expletive Deleted]
>> I understood the weakest point in the system was the potential to
>> intercept point to point microwave transmissions between the network
>> infrastructure, and I think you`d have to pretty game to try that :)
>Don't try this one kids.
Just out of interest, I presume the microwave transmissions are at a very
high frequency? What are the health and network service implications of
putting yourself or another object in between two fixed dishes, (not that I`m
about to try :) ?
>These words are mine, and NOT those of my employer!
As for all of us on this list.
http://www.amiga.com So the world may know...
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