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Hardware Hacking

Is Your GPS Naive? 291

Posted by CmdrTaco
from the what's-a-dikfor-anyway dept.
mi writes "Many GPS devices today will try to scan the FM bands for traffic advisories in the area to display on their screens. The signals, however, are neither authenticated nor encrypted, and one can — with commonly available electronics — construct a device to broadcast bogus advisories. Possible codes range from "bullfight ahead" to "terrorist attack"..."
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Is Your GPS Naive?

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  • by Ph33r th3 g(O)at (592622) on Sunday April 22, 2007 @01:44PM (#18832863)
    "Speed trap ahead."
    • If there isn't one specifically for "speed trap", then re-purpose one of the lesser used code. I'd recommend "bullfight" just because there will be very few instances of its legitimate usage.
      • by garcia (6573)
        I'm really waiting for the day that GPRS (or the like) is used to transmit the positions of those assholes hiding in the medians. Fair is fair. If they're allowed to hide (in OH they seem to have to be in fairly plain sight and have their parking lights on) we should be allowed to do basically the same thing.

        Unfortunately, because local municipalities entire judicial systems are paid from a good percentage of the fees gained from these fines, there is no impartiality and that would be illegal.
        • by portforward (313061) on Sunday April 22, 2007 @03:41PM (#18833661)
          Or alternatively, you could just drive the speed limit.
          • by drsquare (530038)
            Why? The speed limits are stupidly low. You have a duty to break stupid laws. If the speed limit was 5mph, would you follow it?
            • Actually I find the speed limits in my locality to be very reasonable. They are fast where they need to be and slow where they need to be.

              If you have an issue with the speed limits in your town, please contact your local elected officials. Have you ever been to a city council meeting?

              • by mi (197448) <slashdot-2012@virtual-estates.net> on Sunday April 22, 2007 @08:51PM (#18835769) Homepage

                If you have an issue with the speed limits in your town, please contact your local elected officials. Have you ever been to a city council meeting?

                In too many localities police will usually let a local resident off with a warning while ripping others off. This keeps local residents (who attend council meetings) content, and brings easy revenue (people from afar are very unlikely to challenge the tickets in local court) to the town. This selective enforcement gets documented occasionally and is a real bane of highway travel.

                NJ's Governor Corzine just had a nasty accident [yahoo.com], because his driver (a State trooper, no less) was going 91 in a 65 mph zone (Governor's vehicle can only do that in an "emergency"). The governor will take months to recover, because the moron was not wearing his seatbelt. Neither the hypocrite trooper (who had a similar accident a few years ago), nor the hypocrite governor are expected to be punished by law, although tens of thousands drivers are fined in NJ for the same (and lesser) offenses every year — most of them without causing an accident.

                The speed laws are not reasonable — they take neither car's age and quality nor the driver's experience and health into consideration. What's too fast for an inexperienced 17- or half-blind 70-year-old driving a Buick is unreasonably slow for a healthy middle-aged driver driving a BMW...

                • by Namarrgon (105036) on Sunday April 22, 2007 @11:23PM (#18836685) Homepage

                  police will usually let a local resident off with a warning while ripping others off

                  OK, unfair/discriminatory/whatever, sure. But "ripping others off"? Did they break the speed limit or didn't they?

                  a real bane of highway travel

                  I would have said "unsafe drivers" were more of a real problem. A ticket when you break the speed limit may be annoying, but having your family wiped out by (e.g.) a drunk driver or a trucker pushing his alertness limits or a speeding NJ Governor, now THAT's a problem.

                  The speed laws are not reasonable -- they take neither car's age and quality nor the driver's experience and health into consideration.

                  True enough. Of course, it gets complicated if you try to write legislation that codifies something as subjective as car quality and driver experience. The commonly accepted approach is to set the limits at a reasonably low average and to let the cop use his/her discretionary judgment. Perhaps your own car or apparent experience are not sufficiently reassuring - or perhaps the cops have just seen too many middle-aged corpses in wrecked BMWs.

                  You & I can argue about where the limits are set, but it's pointless. The roads are common property, the rules for sharing them are the rules we agreed to abide by when we got our licenses, and there really aren't many times when one simply must drive that fast (hint: they usually involve sirens and flashing lights).

          • That isn't always a good idea [google.com], as this student video proves. 285 loop in Atlanta, during rush hour, people driving side by side, within the speed limit, backing up traffic for miles. Quite funny, and proves the limit is too low.
        • by arivanov (12034) on Sunday April 22, 2007 @03:45PM (#18833705) Homepage
          How uninspiring and unoriginal. Based on my recollections from a brief encounter with Ohio cops 16 years ago I am not surprised in the slightest.

          They should come here across the pond to introduce themselves to the most recent inventions in motorist taxation like:

          The "Accident Assistance Van" and "Yellow Speed Camera Partnership Van". Both are in use by Sussex police and anyone driving along the A14 and A12 can see them on regular basis.

          These vans can be parked with a laser speedgun + CCTV pointed through a window (back, side and front), can be parked behind a hedge with the same laser speedgun + CCTV as the only thing visible on a tripod cabled to the hidden van and most importantly can drive at 3 mph under the speed limit and record the speeds of all who overtake them showing van speed and overtaking vehicle speed.

          I have seen them used in every single one of these modes of operation. In fact, out of all my A14 journeys in the last month there has been only one where I have not seen one them. None of them has proper police markings.

        • by dave420 (699308)
          If you're speeding, you deserve a ticket. It's that simple. Whether the cop's hiding or not does not affect the guilt of the individual. If the municipalities get so much of an income, then that's purely down to people speeding. Speeding is selfish, and frowned upon for a good reason.
          • by sahonen (680948)
            So if the speed limit is set artificially low, you deserve a speeding ticket even if you're travelling at a safe and reasonable speed for the conditions. Got it. People speed because most speed limits are set artifically low to bring in speeding ticket revenue. It's not as bad as 30mph on a freeway, but it's bad enough that travelling the speed limit can be inconvenient.
            • by repvik (96666)
              Do you have any evidence that the speed limits are artificially low, or are you pulling stuff out of your ass?
              • by NMerriam (15122)

                Do you have any evidence that the speed limits are artificially low, or are you pulling stuff out of your ass?

                Here in Texas there are plenty of small towns that have public officials on record as saying this is what they do. It's not like they have to be coy about it -- the only people who dislike it are from out of town and can't vote against them, while the people who DO vote for them (and the stupid limits) are the ones who get taxes reduced by increasing revenue from out-of-towners.

                If you only have 90

              • Re: (Score:3, Insightful)

                by wolrahnaes (632574)
                US 20 here in Ohio has a few areas where it's a 4 lane divided highway, all but identical to Interstate 80 a few miles north, but the speed limit is 45 for no good reason. Corn fields on the right, corn fields on the left, nothing but fucking corn and the ever-present Highway Patrol cars in the median. Along the same route there are also some useless speed trap towns where the speed limit is 25 because one house happens to be close. Again, this is on a 4 or sometimes 5 lane highway and of course there ar
    • by RealSurreal (620564) * on Sunday April 22, 2007 @02:59PM (#18833385)
      Here in the UK I think you'd find it more efficient to broadcast a message when there wasn't a speed trap ahead.
      • by coaxial (28297)
        I would, but I suspect your damn cctv network [engadget.com] will would nag me the rest of the day. ("Excuse me good sir, but might I suggest that you wait until the crosswalk indicates that it is safe to cross? Sir. Sir! You're crossing the street against the light! Sir. For your own safety please obey all safety regulations in the future. Sir, I don't believe that is an appropriate gesture.")
    • Actually, here's an entertaining application for your car.

      Suppose you could transmit an FM signal strong enough to override the "normal" traffic update signal for, say, a half-mile radius inconspicuously. I don't know if that's possible, but bear with me. So you drive down the road while broadcasting that there has been a horrendous accident, bomb scare, or just plain "Closed Road" about five miles ahead of you.

      All those people with their GPSes will immediately get the warning and they'll tell their GPS t
      • by CokeBear (16811)
        Wouldn't work until you hit a critical mass of people using GPS with traffic monitoring.

        Even then, for most people the daily commute is a habit that is not easily broken, and even if they hear about traffic up ahead, few seek an alternate route.
    • by mi (197448)

      It would be nice and easy to do, indeed: you push a button when you drive past the trap and the code, along with your current coordinates gets broadcast.

      Unfortunately, cops will start broadcasting these everywhere themselves — similar to how they put fake traffic cameras and other scarecrows. The justification will be, that it causes people to slow down. The (truly desired) effect will be, that people will start ignoring these signals as noise.

  • by jamestheprogrammer (932405) on Sunday April 22, 2007 @01:48PM (#18832899)
    Why would you have a "terrorist attack" code for a traffic warning system? Okay, so I can see how maybe they might close off streets for emergency personnel, but couldn't you just leave the code at that - "Roads Closed"? I mean, if you go telling drivers that there's a terrorist attack ahead of you, they're going to panic, freak out, and maybe get into a car wreck.
    • by HerrEkberg (971000) on Sunday April 22, 2007 @01:53PM (#18832925) Homepage
      That's the point of the "terrorist attack" code. Terrorists use it to create havoc, panic and destruction.
      • by UbuntuDupe (970646) * on Sunday April 22, 2007 @02:18PM (#18833093) Journal
        Yeah, good point. But WE are smarter than them. So ... hm, what to do. OH!!!! I know! If there's ever a terrorist attack, all of the news networks should just ignore it entirely! That way people will be in complete ignorance that it's happened. (I mean, except maybe for eyewitnesses calling friends and relatives, but that can easily be banned.)

        I mean, informing people about terrorist attacks is just playing into their hands.
        • I mean, informing people about terrorist attacks is just playing into their hands.
          No, but sensationalizing the news reporting is. Did we really need to have regularly programming constantly interrupted during the day because of the recent college shootings? What benefit was there to completely pre-empting much of that day's prime-time programming with 'news' shows pontificating on every little detail of the event?
      • The evil bit (Score:3, Interesting)

        by gr8dude (832945)
        Hmm.. works exactly like the evil bit [wikipedia.org]. In fact, I'm sure that when they broadcast "terrorist code", somewhere in a lower-level function the evil bit is set too!
      • by rhizome (115711)
        That's the point of the "terrorist attack" code. Terrorists use it to create havoc, panic and destruction.

        Wait, I thought that was Dick Cheney's job.
    • Why would you have a "terrorist attack" code for a traffic warning system?

      The idea, James, is that people could nefariously disrupt the public with messages designed to cause hysteria.

    • by arthurpaliden (939626) on Sunday April 22, 2007 @02:04PM (#18832987)
      Because the device has batteries, wires and flashing lights so therefore it must be a terrorist device, hence the code.
    • Re: (Score:2, Funny)

      by hattig (47930)
      I don't think they'd panic.

      They'd merely alter their route so they could meerkat the carnage as they drove past. Heavens Forbid that they miss the chance to see such a disaster with their very own eyes, driving past at 10mph looking to the side rather than straight ahead. Wow, is that a dead body? That's something to tell the kids tonight!
    • by joto (134244)

      Why would you have a "terrorist attack" code for a traffic warning system? Okay, so I can see how maybe they might close off streets for emergency personnel, but couldn't you just leave the code at that - "Roads Closed"? I mean, if you go telling drivers that there's a terrorist attack ahead of you, they're going to panic, freak out, and maybe get into a car wreck.

      The emergency personnel is also driving by GPS. When they see a "roadblock" code, they try to find a different route. If they see a "terrorist

      • That's silly. How do you think Emergency Dispatch works? Give your ambulance crews a GPS and tell them to drive around till they hit a road which is flagged by the traffic advisory system as "Injury Accident"?

        Or, maybe, just maybe, they're given the exact location and enter that, and drive directly there, regardless of what traffic advisories they see?

    • by WarlockD (623872)
      I have a Garmin C340 with the traffic updater. I remember one day, the entire city lit up, with major traffic eveywhere. It made me wonder if someone was playing a trick.

      Not sure how much prank value this thing has. Not many people use this feature, not to mention its not very up to date when it comes to traffic.
    • Re: (Score:3, Informative)

      by RMH101 (636144)
      BECAUSE IT'S NOT A TRAFFIC WARNING SYSTEM! IT'S *RDS*.
      RDS exists to allow FM radios in cars to do fun stuff like retune to a national station as you move around and the frequencies change. It also allows radio broadcasts to be flagged as "traffic" so your radio can automatically tune in and play traffic broadcasts to you.
      In other words, its function is to usefully and automatically tune your FM radio to a new frequency.
      The NBC "terrorism" broadcast flag is designed so that in the godawful scenario whe
  • by Anonymous Coward
    It would be much more fun to try for "Jelly wrestling ahead" and watch people panic TOWARDS the area.
  • Years ago (going on 30 years ago, now), I used to hitch-hike. It was safe then. This would be great for that sort of thing. But I can also see this becoming an annoying advertising tool.
    • Re: (Score:3, Insightful)

      by zCyl (14362)

      But I can also see this becoming an annoying advertising tool.

      I doubt it. You can also broadcast bogus FM radio station signals containing your own advertisements, because News Flash: FM radio is also not authenticated.

      But in the U.S. the FCC regulates these sort of things, and would not take kindly to you broadcasting all over the spectrum without authorization.
      • But in the U.S. the FCC regulates these sort of things, and would not take kindly to you broadcasting all over the spectrum without authorization.

        Who said anything about "unauthorized"? Where there is money to be made by big biz, the FCC is "on-board".

        • In which case they can start their advertising-only radio stations whenever they want.
          • In which case they can start their advertising-only radio stations whenever they want.

            Which will transmit advertising directly to your GPS...

    • by Dun Malg (230075) on Sunday April 22, 2007 @02:43PM (#18833273) Homepage

      Years ago (going on 30 years ago, now), I used to hitch-hike. It was safe then.
      Please. It's still just as safe as it always was (i.e. perfectly safe, unless you're unlucky or alone and female). You think the odd itinerant serial killer didn't used to pick up and murder hitchhikers in the 70's? I can cite you DOZENS of hitchhiker murders from the 70's. The only difference now is that you hear about it on the news, and advances forensic science have led to more conclusions of "definitely murdered hitchhiker", rather than the old separate results of "family in Oregon never hears from hitchhiker again" and "police unable to ID body found by Hwy 8 in Ohio".
  • by vasanth (908280) on Sunday April 22, 2007 @02:01PM (#18832973)
    the writer seems to think encryption can solve this problem, encryption cant help here as the system is unable to communicate back to negotiate the setup, and if the signals are encrypted with a predetermined key it will be susceptible to replay attacks... how different is this to a common radio channel telling its listeners that there's been a terrorist attack etc? the issue seems to be more of a hype than a real concern...
    • by WolfWithoutAClause (162946) on Sunday April 22, 2007 @02:09PM (#18833035) Homepage
      It [i]could[/i] work if public key encryption was used for authentication, and the messages were timestamped and geolocated to prevent replay attacks.
      • by joto (134244)

        It [i]could[/i] work if public key encryption was used for authentication, and the messages were timestamped and geolocated to prevent replay attacks.

        Uhm, either all GPS devices and all such public service transmitters would need the encryption code, which is not secure. Or, the process would rely on users actually typing in the public part of an authentication code for the area they visited, which would mean the system would never work because most users would find that a hassle.

        • Well, there could be a single centralised signature authority that signs messages sent to it with a single private key, the centralised authority would have to implement some kind of separate authentication scheme to make sure that they only sign messages from people that are authenticated to help ensure that they don't end up signing messages from bad guys.

          It doesn't have to be perfect it just has to be good enough. Perfect security doesn't exist.

    • by Shadowlore (10860)
      That is a result of the focus on security theater instead of real security. When the alleged security is hype, we will see more hype about it's problems, real or imagined.
    • If the signals are encrypted with a predetermined key it will be susceptible to replay attacks

      Replay attacks could be prevented by making the messages spacetime specific - GPS systems rely on very accurate timekeeping, so it should be easy enough to make GPS units throw away messages that came at times that disagree with the message's own internal time (which could not be altered without breaking the encryption).

      I fail to see how this could be successfully replayed under those circumstances.

  • I have a hunch that their definition of "off the shelf equipment" varies significantly from that of the average slashdotter.

    There are plenty of extremely simple radio transmission that would be even easier to hack. One that comes to mind are the (rather dated) tones broadcast locally to set off EMS / Fire pagers. Another would be the National Weather Service alerts.

    Dan East
    • On the other hand, one has to weigh the amusement/entertainment factor against the resulting Federal terrorism charges and corresponding prison sentence.
  • You'll have, what maybe one guy do this just to see if it works?

    PLease, a little less fearmongering.
    • by timeOday (582209)
      And what's to stop a pirate radio station from broadcasting false traffic reports or news by regular old analog voice transmission? Nothing. Somehow the world keeps turning.
  • by abb3w (696381)
    What is the code number for "Martian Invasion"?
  • Sounds familiar... (Score:5, Interesting)

    by Tim Browse (9263) on Sunday April 22, 2007 @03:20PM (#18833511)
    ...I still think this [bbc.co.uk] is funnier.
  • That's why they are called advisories. In fact, it may be useful to give truck drivers transmitters to warn people that their truck fscked the freeway. FM radio itself is not authenticated and anyone can transmit some urban legends on radiowaves. We just need to remember that not everything is secured and treat outrageous news with a grain of salt.
  • My GPS has an FM traffic receiver, but I don't detour because of information provided by it. I get confirmation and further information from XM traffic, then I decide whether to detour or not.
  • I'd like to have something to make my morning commutes quicker. TomTom and a few others can receive traffic reports. If a report of a traffic jam is received, the user is given the option to detour around the traffic jam. Now if I get get everyone to detour around my daily commute route...
  • Radio Maryja, polish catholic radio with some extreme views on jews, EU etc (the same thing according to them ;)) used fake RDS for traffic announcements (TA, TP) few years ago. Drivers with RDS-enabled car stereos usually have their radios set to switch to such broadcast automatically so they often had to turn this option off entirely. Radio Maryja doesn't do that anymore, at least here, but there was a time when this was serious problem, they get away with many illegal radio practices :/
  • ok so. 7.45 I leave for work every day and every day my satnav tells me the fastest route to take[1] based on the speed limit of the various roads. However, there are traffic lights and traffic on the route suggested, I can't get anywhere near the speed limit... The satnav is operating on incorrect information.

    However. It knows the true average speed along those roads at those times of day because it's actually following the route. All it has to do is to store, and use the stored average speed information f
  • http://dev.inversepath.com/rds/ [inversepath.com]

    go to the source of the guys that did it. The info that the article decided to leave out.

  • Did you know that your neighbor has a set of deadly sharp steel knives in their kitchen? At any moment, they may crack, hack you and your family into small pieces, and feed them to the cat! They could be outside your front door right now!
  • This could be useful (Score:3, Interesting)

    by Rix (54095) on Sunday April 22, 2007 @06:58PM (#18835135)
    Construction crews could warn people of their presence around corners or hills, neighbourhoods could set up a "children playing" zone, et cetera.
  • Post schematics or it isn't possible to do this.

Make sure your code does nothing gracefully.

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