On Jul 9, 2010, at 1:00 PM, Pawel wrote:


Hi,

On Apr 27, 2010, at 5:38 AM, "Peter Gutmann (alt)" <pgut001.reflec...@gmail.com > wrote:

GPS tracking units that you can fit to your car to track where your kids are taking it.... [T]he sorts of places that'll sell you card skimmers and RFID cloners have started selling miniature GPS jammers that plug into cigarette-lighter sockets on cars.... In other words these are specifically designed to stop cars from being tracked.

(Some of the more sophisticated trackers will fall back to 3G GSM- based tracking via UMTS modems if they lose the GPS signal, it'll be interested to see how long it takes before the jammers are updated to deal with 3G signals as well, hopefully while leaving 2G intact for phonecalls).

Just wondering, why wouldn't GPS trackers use 2G to determine the location?

And, also, does it even need a cell service subscription for location determination, or is it enough to query the cell towers (through some handshake protocols) to figure out the proximities and coordinates?
The 2G stuff wasn't designed to provide location information; that was hacked in (by triangulating information received at multiple towers) after the fact. I don't know that anyone has tried to do it from the receiver side - it seems difficult, and would probably require building specialized receiver modules (expensive). 3G provides location information as a standard service, so it's cheap and easy.

The next attack, of course, is to use WiFi base station triangulation. That's widely and cheaply available already, and quite accurate in many areas. (It doesn't work out in the countryside if you're far enough from buildings, but then you don't have to go more than 60 miles or so from NYC to get to areas with no cell service, either.) The signals are much stronger, and you can get location data with much less information, so jamming would be more of a challenge. Still, I expect we'll see that in the spy vs. spy race.

I wrote message to Risks - that seems to never have appeared - citing an article about GPS spoofing. (I've included it below.) In the spy vs. spy game, of course, it's much more suspicious if the GPS suddenly stops working than if it shows you've gone to the supermarket. Of course, WiFi (and presumably UMTS equipment, though that might be harder) can also be spoofed. I had an experience - described in another RISKS article - in which WiFi-based location suddenly teleported me from Manhattan to the Riviera - apparently because I was driving past a cruise ship in dock and its on-board WiFi had been sampled while it was in Europe.
                                                        -- Jerry


The BBC reports (http://news.bbc.co.uk/2/hi/science/nature/ 8533157.stm) on the growing threat of jamming to satellite navigation systems. The fundamental vulnerability of all the systems - GPS, the Russian Glonass, and the European Galileo - is the very low power of the transmissions. (Nice analogy: A satellite puts out less power than a car headlight, illuminating more than a third of the Earth's surface from 20,000 kilometers.) Jammers - which simply overwhelm the satellite signal - are increasingly available on-line. According to the article, low-powered hand-held versions cost less than £100, run for hours on a battery, and can confuse receivers tens of kilometers away.

The newer threat is from spoofers, which can project a false location. This still costs "thousands", but the price will inevitably come down.

A test done in 2008 showed that it was easy to badly spoof ships off the English coast, causing them to read locations anywhere from Ireland to Scandinavia.

Beyond simple hacking - someone is quoted saying "You can consider GPS a little like computers before the first virus - if I had stood here before then and cried about the risks, you would've asked 'why would anyone bother?'." - among the possible vulnerabilities are to high- value cargo, armored cars, and rental cars tracked by GPS. As we build more and more "location-aware" services, we are inherently building more "false-location-vulnerable" services at the same time.

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