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Network Communications Security Wireless Networking Technology

Battery-Powered Transmitter Could Crash A City's 4G Network 121

DavidGilbert99 writes "With a £400 transmitter, a laptop and a little knowledge you could bring down an entire city's high-speed 4G network. This information comes from research carried out in the U.S. into the possibility of using LTE networks as the basis for a next-generation emergency response communications system. Jeff Reed, director of the wireless research group at Virginia Tech, along with research assistant Marc Lichtman, described the vulnerabilities to the National Telecommunications and Information Administration, which advises the White House on telecom and information policy. 'If LTE technology is to be used for the air interface of the public safety network, then we should consider the types of jamming attacks that could occur five or ten years from now (PDF). It is very possible for radio jamming to accompany a terrorist attack, for the purpose of preventing communications and increasing destruction,' Reed said."
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Battery-Powered Transmitter Could Crash A City's 4G Network

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  • by Anonymous Coward on Wednesday November 14, 2012 @03:39PM (#41983403)

    AT+T has apparently been using this for months, in almost every major city

  • Invasion! (Score:2, Funny)

    by jdkc4d ( 659944 )
    A communications disruption can only mean one thing...
  • What's the point? (Score:5, Informative)

    by rabtech ( 223758 ) on Wednesday November 14, 2012 @03:45PM (#41983489) Homepage

    What's the point here? You can do the same thing with all the proprietary public safety network gear various vendors are peddling - they are mostly hilariously insecure. Or if you have a portable generator, just flood the public safety band with interference. It accomplishes the same thing.

    The article claims older 3G and 2G networks would still work if LTE were jammed but that's completely false. There are a ton of ways to jam those by using fake femtocell pilot signals or otherwise interfering with synchronization signals.

    In fact the MIMO technology of LTE could make it slightly harder to jam if the base stations are properly filtering stray signals. Use car-mounted MIMO for the user-side and you would get something way better than any of the existing systems at resisting interference.

    • by arth1 ( 260657 )

      What I want to know is whether this will take out 4G, as the first link states, or is limited to LTE, which the rest of the submission talks about.

      4G LTE != 4G

    • Mod parent up. (Score:4, Insightful)

      by khasim ( 1285 ) <> on Wednesday November 14, 2012 @04:04PM (#41983735)

      I don't know what the line:

      With a £400 transmitter, a laptop and a little knowledge you could bring down an entire city's high-speed 4G network.

      came from but it is 100% false (unless you are talking about a very, very small "city".

      This "attack" is just broadcasting noise and messing with communication protocols. So the range is limited to the coverage area of the transmitter. Including dead zones where there is too much concrete and steel for the transmitter to get through.

      So you should see the same pattern for blocking as you do for regular access. With a similar requirement for blocking as for coverage.

      • > 100% false (unless you are talking about a very, very small "city".

        And don't forget antenna location. As a general rule, higher is better. If you're trying to jam an entire city from a car in the street, you'd have to radiate so much power that your alternator would whine and your brain would become ... warm. :)

        Be better from the top of tall building, but now you can easily be located and dealt with. Unless you're spiderman and can leap from one building to the next, that is. Or, you don't think anyone

      • by AmiMoJo ( 196126 ) *

        Note that TFA didn't state what type of batteries this thing needs. 50,000 AA cells should take out most medium sized cities.

    • I think most large emergency response teams now use an encrypted radio w/ hopsets configured. Like the military gear, it jumps channels very rapidly. It makes the signal very difficult to jam. You would have to block out a wide swath of frequency to do so effectively. I know that major cities in California started making the switch back in 2005. I would expect any major city in the US to have already switched by now.
    • by Anonymous Coward

      RTFA, and I am a communications engineer.

      The article clearly states that the issue with 4G is that it's extremely sensitive to synchronization of transmitter / receiver. It doesn't require much power to disrupt this. Older networks (2G, 3G) are less prone to this issue, so it becomes less practical to jam and entire city.

      Setting up picocells / femtocells can trick phones, but again, people who understand the protocols better than you or myself (the people who did this research) determined that this is les

  • Transmitting some random packets with the WiFi card.
    There are many things you can do on the low level link.

    Certainly, when in some hotel there is the paywalled internet asking for like $20/day, it is possible to sniff the traffic, find some MAC address that paid, and pretend to be him/her. There is nothing that could be done to prevent such hacks. Not that I recommend doing this. Please don't do this, this is illegal. I am just saying this is possible.

    • When I was in college and wifi routers were just getting to the point where they were affordable enough for a regular person to buy, whole dorms would go out when people switched the WAN/LAN connections. Campus didn't have wireless yet, and the IT guys would get all upset and start going from room to room trying to find who had the mis-installed routers. Happened after every break.
      • At the uni i'm at they banned the things in dorms, probablly partly for that reason and partly also they didn't want students letting just anyone onto the network.

        BTW you can now get switches with port protection features that will protect against rogue DHCP servers like this.

  • Got several amateur radios in my truck so no cell towers needed.
  • Imagine blocking all traffic lights so nobody can see if they are red and green, and see what happens to the traffic.

    Actually if I were a bad guy I would turn all lights green instead of disabling them... there'd be a crash at every intersection!

    • by vlm ( 69642 )

      Traditionally (depends on where you live) turning on the green throws a relay shorting the filament on the opposite green. So if you try two greens at once, it blows the fuse/circuit breaker, because fuses don't like short circuits. This is tricky and your timer needs at least a fraction of a second of dead time where its red all around.

      Another fun way to wire it up, is 240v with 120 lamps, hot, to green light, to the red and yellow opposite, and from either red or yellow to neutral. This makes the midni

      • Damn those completely sealed units in my city full of LED's. You'd have to break into the control box, which would probably trigger a tamper switch.
    • Imagine blocking all traffic lights so nobody can see if they are red and green, and see what happens to the traffic.

      Actually if I were a bad guy I would turn all lights green instead of disabling them... there'd be a crash at every intersection!

      Where I live, just turning the lights off (or switching to flashing red) works just the same.

      Happens every time a storm rolls through. I'd find it funny if I didn't have to share the road with idiots.

  • I guess the only solution to wireless signal jamming is to go back in time and start using Police Boxes [], again.

  • The 4G service they offer isn't really there! Brilliant!

    • by afidel ( 530433 )

      Huh? Sprint had the first 4G network with WiMax and is currently in the process of rolling out LTE. By the end of 2014 everywhere that currently has Sprint 3G service will have LTE coverage and most towers will have fiber backhauls which is significantly more ambitious than the big 2.

  • I do IT on yachts and heard a story of a yacht that had cell repeaters on board. The installation company had the power cranked all the way to 11 and knocked an entire coastal town's cell service out while they were in port. Vodafone politely asked them to turn that shit off.

    At a wireless training session with one of our vendors they said that the US navy aircraft carriers jam all radio transmissions when they enter port. That sounds like a bit of a frustration.

    • Vodafone politely asked them to turn that shit off.

      ...which wasn't hard to do because all vodafone had to do was call anyone in that town and it rang straight to the yacht...

  • by Anonymous Coward

    Because rather then fix the problem in the system its self, they will just ban the 'small radio transmitter' that is under your control.

  • Can I^Han adversary jam first-responder and other emergency radio networks this easily?

    What about the "if all else fails" ham-radio networks? Imagine if the aliens in Independence Day had jammed the entire usable radio spectrum. No more more-code-gets-the-word-out moving ending.

    • They couldn't have. They used the satcommunication to coordinate their attacks. If they would have jammed it they wouldn't have been able to use it themselves. (Of course they were so awesome they should have had their own satellites, but that's suspension of disbelief)
  • You can jam radio frequency communications with a sufficiently powerful and/or noisy signal on the same frequency? Who would have thought? I realize that the article is more about LTE's weaknesses, but trying to play it off as some national security weakness is total fearmongering. Even if LTE is inherently weak against jamming attacks (which is probably by design for the "authorities" to shut it off as they please), so what if one idiot can jam one cell site? (which is what the article really says if yo
    • by Anonymous Coward

      And why the hell would first responders/emergency workers be using LTE for anything critical, anyway?

      Actually, they ARE going to be using LTE for public safety. The next generation public safety network (which may be used for decades) is going to use LTE on the public safety bands. The whole point of this article was to raise awareness and add some jamming mitigation before it gets put into the public safety network.

      • I don't doubt that they are planning to use LTE for public safety, I just question why they would *want* to use LTE for public safety. It's super-fast, but that's where the benefits end from what I've seen. It seems to have mediocre propagation characteristics even at low frequencies, every LTE device I've ever seen will intermittently drop the connection then take a few minutes to restart it, and does indeed seem to have issues with interference in addition to questionable performance in situations with
  • by superid ( 46543 ) on Wednesday November 14, 2012 @04:44PM (#41984257) Homepage

    I hate to say it but 4G for an emergency network is just a money sink. I hate to have a defeatist attitude but at least in my small new england town this would be a complete waste of time and money and effort. We have no unified dispatch system. All land line 911 calls go to police. If you want Fire or Ambulance it's transferred to the Fire department, who then transfers medical calls to the ambulance. If you call from a cell phone it goes to the state police regional office first, then to the local state police barracks, then to town police, etc. Police and fire are on separate frequencies. ICS is a joke and never implemented. EMA is run with all donated equipment and goodwill of Ham operators. Better than nothing? certainly but not by much. I put an IP camera onto their EMA vehicle, punched a hole in their firewall and the chiefs were able to view the scene and control the camera from the EOC. It took me 10 minutes but it was like the natives seeing an airplane. The average Police/fire/EMA chief is 50+ years old and typically holds a grease pencil, not an iPad.

    Example, there was a mill fire in the neighboring city. Multiple towns responded. No ICS, no communication plan, everyone on one channel walking all over each other. There is no way any of these communities could implement, monitor or effectively use a 4G solution.

  • Thank God there's no real 4G yet ;-)
  • Far more fun and a better use of money to disable the police band. Every easy in the US for police departments that do not encrypt their communications.
  • I want loud drums in Morse Code!

  • You're looking at it all wrong. Terrorists needn't go through the effort of attacking a military might at all. Just take down all communications in a city, and watch the mayhem.

    Aside from huge inconvenience, and a whopping expense to resolve the problems, there's so much more. Businesses stop working. Security alarms stop working -- which doesn't matter because the traffic alone will stop any timely response. Here comes the looting, followed closely by the rioting.

    It's not the end of the world, and it'

    • Don't take down comms, take down power in a way that doesn't allow it to come back up quickly/cleanly and then you will see the real carnage. Just look at NYC for an idea of what can happen...
    • It's not the end of the world, and it'll all get resolved in a day or two; but that's a day or two of mayhem, followed by a couple weeks of clean-up. And it all cost $500 to the terrorist -- which can just as easily be a local. Or worse, a local with an imported cellphone, who doesn't know that he's the one causing the mayhem.

      Dude, you can't take down an entire city's communication network with a $500 box or a screwed-up handset. You could jam one cell site, at best. Probably only one sector of one cell site, though. On one carrier. Stop spreading this FUD and bullshit.

      In the scenario described in TFA, landlines would still work, 2G would still work, 3G would still work, 4G LTE data might be down on one carrier (in the geographic area covered by one sector of one cell site), but the other carriers and every other sector o

      • 2G, 3G, and landlines won't exist in five years.
        This article talks about police radios going to lte.
        No one has walkie talkies anymore.
        Multiple carriers roam on eachothers' networks, and share cell sites.
        One sector of one tower of one carrier is enough to cover an entire office building.
        Overlapping towers can quickly become over-saturated in the absense of a single one.

        You're correct that it's all FUD. But not because it can't work exactly that way. Only because terrorists are monumentally stupid and can't

  • But government wants to shut off communications anyway to hinder coordination or remotely-detonated bombs.

    So cutting off communication increases damage, as does leaving it running?

  • stop pointing out the weak spots and giving the terrorists ideas!
  • Of course its possible to cause havok.

  • You can jam any electromagnetic-based transmission signal by blast "loud" enough static. I think we've known that for like 80 years or something, just everyone ignored it.

Logic is a pretty flower that smells bad.