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From : Cmystery
To : saintly
User Comment : Trust me your expertise is helpful and does put me in the right direction. Thank you so much for sharing your knowledge.
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Message Status : Confidential

[08-18-2000] Cmystery : I am a Mystery/Suspense writer that would appreciate a bit of technical advice regarding how a hacker/cracker could conceivably use a lap top computer to deceive police about their location during a live chat - and how police could track him/her and pick up their signal? If it is not possible I will still be sincerely thankful if some expert out there can point me in the right direction to do some research where I might get information that I could put together to end up as a convincing read. Thank you in advance
[08-18-2000] saintly :
Most things that rely on computers can be manipulated by a sufficiently skilled hacker.

To the best of my understanding on how traces work, they work very differently for normal telephone (over a hard line) and cellular.

When a cellular call is placed, the phone sends out a signal. Several nearby towers may pick up the signal, and the one that has the strongest reception delivers the call. You can calculate where the person is calling from easily by looking at the different signal strengths together with the known locations of the towers.
I would assume that a hacker who had broken into several towers could detect his own incoming call and force the towers to report that his signal was at a different strength than it actually was. S/he could either randomly bias the signals and make the call appear to originate somewhere else (if not done carefully, then the nearest tower would not be handling the call; the call would be weaker than normal with more static) or bias it specifically to make it appear to come from a specific area. Since the same set of towers is involved, you shouldn't be able to bias it very much out of your immediate area. If you tried to make it look as if your call was coming from the next county, you should reasonably expect that towers in the next county would be the ones reporting. I might expect anywhere from a few blocks in a city to a mile away or so in a rural area would be reasonable. It would be fairly tricky to do, and you'd have to keep a continuous watch (or have a program that kept a watch) to make sure the numbers stayed accurate, since the towers are continuously evaluating the signal in case you move.

Of course, so would hacking into the cell towers, which would involve physically travelling to them at some point to set up special equipment (since I doubt the towers are connected to the Internet). It *might* be possible to break into one tower and thereby be on a network; allowing you to break into the rest somehow.

That would be the coolest way. A sufficiently skilled hacker who knows phone hardware as well might change the frequency of her phone to one the towers aren't listening for, then set up several special "relay" transmitters. The other relay transmitters would listen for the modified frequency and re-broadcast it at the original frequency of the phone. That would be another way of displacing the signal to the location of the relay transmitter. You could have several relays, and use the laptop to inject special signals or decide which relay should handle the call. You could make your call appear to jump across the map between relay locations. You would have to make your call in the range of one of your own relay towers.

In either case, some prior setup is required. In the first, you have to hack into the actual cell towers you are going to use and set them up to be accessed later when you are making your cell call. In the second case, you have to set up your own equipment beforehand and stay in their range.

In the first case, the police could figure out what towers were being hacked into (once they figured out that was what you were doing). They could simultaneously kick the hacker out of the systems (and kill any running programs the cracker is using), and suddenly all the towers would be reporting the correct location. In the second case, they find one of the relay towers, figure out what the modified cell frequency is and set up their own equipment to listen for and triangulate the hacker. In that case, the cracker might have several such relay locations set up and could move to the next. Both cases work best if they can zero in on the cracker while the cracker is still talking to them.

Over a hard line, I gather that when you make a call, it goes through several locations and switching stations. Tracing a connection means starting from your end of it, asking the phone company what your line and switch are, then asking your switch what line your line is connected to, then asking what *that* line is connected to, etc.. Maybe this has changed in the era of caller-id. A sufficiently skilled cracker might be able to hack in, watch for the trace to start and hijack it; force the phone switch to report an incorrect line when it is asked what one line connects to.

Or just set up several locations with 'call-forwarding'. That would have the same effect, the police would have to find out who called who, and the hacker could make one of the phone switches along the way report the wrong number...

The same way, if the police find the computer that has been cracked into, they boot the cracker and suddenly everything works again.

Any time they boot the hacker from a system, the hacker knows and can take responsive action. It would take a lot more skill to find the buried information the hacker is trying to suppress without tipping off the hacker...

Does this help?
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