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Networking Hardware Hacking Wireless Networking

Jamming Wi-Fi With a $15 Dongle 136

An anonymous reader writes with this report about just how easy it is to disrupt if not entirely kill modern consumer-grade networks -- not just Wi-Fi, but Bluetooth and Zigbee networks, too. Crucial to determining the likelihood of any given kind of attack, though, is how much it would cost the attacker to attempt. The bad news for network owners and users is that it doesn't cost much at all: "According to Mathy Vanhoef, a PhD student at KU Leuven (Belgium), it can easily be done by using a Wi-Fi $15 dongle bought off Amazon, a Raspberry Pi board, and an amplifier that will broaden the range of the attack to some 120 meters."
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Jamming Wi-Fi With a $15 Dongle

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  • With a $15 dongle? (Score:5, Insightful)

    by aardvarkjoe ( 156801 ) on Tuesday October 13, 2015 @11:56AM (#50718097)

    ...it can easily be done by using a Wi-Fi $15 dongle bought off Amazon, a Raspberry Pi board, and an amplifier that will broaden the range of the attack to some 120 meters.

    In other news, I can build myself a car with a $3 roll of duct tape bought off Amazon, as long as I happen to have all the other pieces sitting in my garage. Astounding!

    • by GuB-42 ( 2483988 )

      It is not really the point here but I hate it when I see "build X with $5" when you actually need at least $100 worth of junk that, somehow, every people must have. And that's not counting the tools.

      • I know!

        And they never even account for the costs of the person's education or years of experience.
        They don't list the cost of the the facility where a project like this can be built without being rained on.
        Or the health care over the years to ensure that one's hands and mind function adequately for the task.
        They don't even account for the cost of the calories of food required for thought and motor control.

        This project would actually cost >$1,000,000

        Seriously though, if you are committed to a hobby, there

    • Misleading title indeed. I think what is worthy of attention here is that wireless "security" cameras aren't very useful unless they actively shift their frequency and amplitude based on the environment, and send out an alert along the lines of, "We are under attack" through cable means. Hey, there's an idea, too bad frequencies to shift inbetween are severly limited by regulation but should thwart a noob with a powerful transmitter.
    • A trembler coil and a spark plug do a pretty good job too. Put it in a headlight and the interference is directional.

  • by Anonymous Coward

    Probably any reasonably advanced ham operator could pull this off for nothing more than his/her labor and the parts in the junk drawer.

    • Heck, I had a Bright House modem that decided to jam all WiFi in my house, and it did it for free. That was a fun conversation with support. Trying to help a "just reboot" monkey to understand that when the modern was on, every WiFi networks within 100 meters on it became useless.
  • PhD (Score:5, Funny)

    by darkain ( 749283 ) on Tuesday October 13, 2015 @11:58AM (#50718109) Homepage

    Wait, it took a PhD student to figure out that broadcasting malicious signals disrupts signals on the similar wavelengths? And OMGs it effects BlueTooth, too!? Totally didn't know that two personal usage wireless communication specs would both be using unlicensed spectrum, WHO WOULDA THOUGHT!?

    I can do it for quite a bit less. Just put a small piece of plastic into the door switch of a microwave so it thinks it is closed, but leave it open. Now turn it on. You can cook yourself while killing Wifi all throughout the house! [DISCLAIMER, DON'T ACTUALLY DO THIS]

    • by Lumpy ( 12016 )

      It's just proof that a "phd" doesnt mean shit nowdays.

      Most garage tinkerers knew this, many of them with high school only education.

      • by Anonymous Coward

        Idiot.
        "During his recent presentation at BruCON, Vanhoef explained that by modifying the dongle's firmware he was able to force the target networks to always give priority to the device's transmissions. If the device is made to transmit continuously, it means that all other devices won't be able to, making the channel effectively unusable.
        His attempts at selective jamming (blocking specific packets) have been less successful, and he concluded that 100% reliable selective jamming is not possible.
        He also says

        • by darkain ( 749283 )

          So basically, this is EXACTLY what was already done back in 2009 then? Back when TKIP was broken using QoS packets to break encryption and establish MitM attacks on Wifi? So, what's new here?

      • by Lou57 ( 78812 )

        It's just proof that a "phd" doesnt mean shit nowdays.

        Actually, it does. I was always told that:

        BS = bullshit
        MS = more shit
        PHD = Piled Higher and Deeper

        • by rtb61 ( 674572 )

          Consider you theory of doctorates next time you need to visit a medical doctor or dentist, I'm sure it makes you feel all warm and cost inside. The only reason there is pride in ignorance is because of that ignorance.

    • Brute force is easy. From the article, he flashed the $15 dongle to take priority over the WLAN and prevents others from TX'ing. He's not just raising the noise floor. This makes it a little harder to detect. I guess if you had a spectrum analyzer or were looking at the RSSI you would see an abnormally strong signal. If you were paying attention to your WLAN, you'd see a device that -potentially- wasn't part of the WLAN broadcasting and supressing everyone else. I'm at work so I can't read more of it, but,
      • So, to paraphrase, '802.11whatever is a 'listen then talk' protocol, so, logic-ally speaking, if we comment out the 'listen' part of the code, it will just talk, and nothing else will talk! GENIUS!'

        Guess what! Ethernet expects only the device who has a given IP to respond to arp requests! If we respond anyway, there will be CHAOS! BWAHAHAHA!

        • "So, to paraphrase, '802.11whatever is a 'listen then talk' protocol, so, logic-ally speaking, if we comment out the 'listen' part of the code, it will just talk, and nothing else will talk! GENIUS!'"

          Every girl could have told you that.

  • by Anonymous Coward

    and an amplifier that will broaden the range of the attack to some 120 meters

  • by tepples ( 727027 ) <tepples@ g m ail.com> on Tuesday October 13, 2015 @12:00PM (#50718125) Homepage Journal

    "This is illegal, you know." [youtube.com]

    Marriott got fined over half a million dollars [slashdot.org] for jamming guests' Wi-Fi.

    • I don't think that would matter to most of those who would have a reason to use something like this. Whether or not it's illegal, it's worth studying.
    • Marriott got fined over half a million dollars for jamming guests' Wi-Fi.

      And you can't afford the same lawyers as Marriott.

  • Wifi. (Score:5, Insightful)

    by ledow ( 319597 ) on Tuesday October 13, 2015 @12:15PM (#50718269) Homepage

    Are you using unlicensed Wifi spectrum for anything mission critical, such that jamming would be anything more than a slight inconvenience?

    More fool you.

    • by Anonymous Coward
      There are vendors peddling wifi for industrial controls [siemens.com] (including safety and emergency control). What could possibly go wrong?
    • Yup. Disrupting wi-fi, bluetooth, and zigbee networks should cause inconvenience only, nothing of real value is damaged. Cutting the wires though causes real problems.

    • by Holi ( 250190 )
      You mean the ISM bands. It's not the "wifi spectrum".
  • In other news... (Score:5, Insightful)

    by SecurityGuy ( 217807 ) on Tuesday October 13, 2015 @12:19PM (#50718331)

    ...did you know that you can render a car inoperable with a device as simple and cheap as a nail? That you can destroy many electronics simply by getting them wet? That you can harm a person simply by swinging a fist into them? Etc, etc, etc.

    Yes, we know this. For many things, it's not possible to make them unbreakable, therefore we enact societal consequences for breaking them like jail, fines, etc. It's been that was for, well, all of recorded history.

    • by mike449 ( 238450 )

      WiFi jamming can be concealed, and detecting the source is much more difficult and expensive (at the moment) than operating it.
      It is closer to anonymous bullying on the Internet than to physical assault. The consequences are much less immediate, meaning that sociopaths are more likely to use WiFi jammers than going around smashing cars and randomly beating people.

  • Someone just realized Microwave Ovens can be used to jam wifi.
    • I had one of those.

      Had to replace both the microwave and the WiFi router to find a combination that worked together.

      I bet the microwave was cheaper than TFA's hardware set up, and one-button simple. And also warmed Hot Pockets better.

  • They wont even allow cell-jammers in prisons where contraband cellphones are everywhere.
    • by gstoddart ( 321705 ) on Tuesday October 13, 2015 @12:35PM (#50718473) Homepage

      First off .. it's Belgium, so not so much with the FCC.

      But, really, if you assume a malicious actor, why the hell would they care?

      If it's cheap and easy to do it, people probably will. It's not like the FCC (or any other agency) has the ability to prevent the attacks just by saying you're not allowed to do it.

      • It's not like the FCC (or any other agency) has the ability to prevent the attacks just by saying you're not allowed to do it.

        Quick, apply that logic to hand guns....

        Enforcement by the FCC may be a rare event, but it DOES happen. Generally you don't get caught directly by the FCC, you get turned in to the FCC by somebody who is being interfered with. The FCC might not be able fine you until they actually observe you breaking the rules, but they do often threaten to levy fines for radio frequency interference complaints. So there is *some* risk of getting into trouble for people who break the rules and run jammers.

      • by bmo ( 77928 )

        >It's not like the FCC (or any other agency) has the ability to prevent the attacks

        They don't.

        They don't generally have the staff to hunt down pirate stations and things throwing out QRM (Amateur talk for interference).

        They have a whole army of Amateurs who will gladly do it for them. It's a game of sorts...

        --
        BMO

  • by cdrudge ( 68377 ) on Tuesday October 13, 2015 @12:47PM (#50718569) Homepage

    With the above mentioned networks being crucial to the functioning of many IoT devices and systems - home security systems, car locks, baby monitors, and so on - it should be obvious that the fact that these attacks can be performed so easily and cheaply may lead to serious consequences.

    If your IoT device, home security system, car locks, baby monitors, and so on have serious consequences if their crucial wireless network is unavailable, you have a serious design flaw in your system. At worst, it should result in the particular thing not communicating and you resort to a back up method, such as say a door lock, a key, or going and checking on your kid in person...

    • My setup has minor consequences. If something's jamming the WiFi, I can't watch streaming video in the TV room, or do anything from downstairs. It's still illegal, it's just that I won't be suing the jammer (if the jammer can be found) for further damages.

  • About 20 minutes into the presentation, the guy demoes it (works!), and then says that
    he is not releasing the code because it could cause trouble.

    Duh!

  • On the flip side, anyone who does do this with said $15 dongle can consequently be located by a resourceful and pissed-off individual using an even cheaper dongle [amazon.com], who can then decide on the proper payba...er...action to take.

  • Dealextreme used to sell a wifi/cell phone/bluetooth blocker for something like $10.. I have a friend that bought one.. I just went looking though, and it looks like they don't cell them anymore.. Maybe they're trying to seem to be more of a legitimate company or something..

  • by superwiz ( 655733 )
    You can just turn your microwave oven. It'll do a pretty good job of interfering with WiFI frequency (which is in the microwave band)
    • by Anonymous Coward

      But my Wi-Fi is 5GHz

      • Does it help? The total amplitude of the ovens is so much higher than anything any wifi antenna should ever put out (without frying anyone standing next to it) that what the oven leaks into its surrounding band should be enough to interfere with most WiFi channels. http://mars.nasa.gov/MPF/rover... [nasa.gov]
  • by Anonymous Coward

    For $15, approximately, (certainly for less than the cost of the Dongle, the RaspPi, and the amplifier) you can get something like a Model T spark coil (aka ignition coil, trembler coil, etc) and a battery and generate enough RF noise to swamp anything in the vicinity.

    For extra fun, google pocket tesla coil or portable tesla coil.

    • For $15, approximately, (certainly for less than the cost of the Dongle, the RaspPi, and the amplifier) you can get something like a Model T spark coil (aka ignition coil, trembler coil, etc) and a battery and generate enough RF noise to swamp anything in the vicinity.

      For extra fun, google pocket tesla coil or portable tesla coil.

      model t spark coils are expensive these days, particularly if they come with any sort of guarantee of functionality.

  • Narrator: Thinking quickly, Dave constructs a homemade megaphone using only a squirrel, some string and a megaphone.

  • by nehumanuscrede ( 624750 ) on Tuesday October 13, 2015 @04:38PM (#50720567)

    I suppose walking about with a dongle sized piece of hardware is a bit more subtle than toting around a microwave attached to a backpack. :D

    • I suppose walking about with a dongle sized piece of hardware is a bit more subtle than toting around a microwave attached to a backpack. :D

      if you get caught walking around with your dongle sized piece of hardware, you could end up on the sex offender list.

  • There is nothing intelligent about these sort of simple disruptive attacks, they are nothing more than a form of temporary vandalism. I could probably to a hell of a lot more damage with the guts of an appliance found in most kitchens, but would it prove I am smart? No.
  • i bet i could do it with a lamp somebody threw away because the cord sparks like crazy where it attaches to the plug.
  • I think I saw this on an episode of Burn Notice...

CChheecckk yyoouurr dduupplleexx sswwiittcchh..

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