3 ms·

The dumping of energy into noise in bands variants tend to be very short ranged because of physics. Malicious clients/APs need much less energy to DoS a networ

The dumping of energy into noise in bands variants tend to be very short ranged because of physics. Malicious clients/APs need much less energy to DoS a network Wi-Fi network. WPA3 adds optional PMF (802.11w) to protect against rogue deauth over WPA2. Also, not deploying 802.11r but deploying WPA-3 only mode and device/user cert-based 802.1x auth also help.

gh02t 2y ago
> The dumping of energy into noise in bands variants tend to be very short ranged because of physics. Sure, but compliant Wifi devices use miniscule transmit power. If you're a criminal you can easily hook up a car battery/generator to a 1000 W transmitter and cover a pretty wide area, or use a directional antenna to focus it a bit more on your target. These sorts of jammers definitely exist, too. Downside though is you're also lighting a huge beacon that says "HELLO I AM DOING SOMETHING ILLEGAL", so you will not be able to keep it up forever. Protocol-based attacks are more discrete, but newer APs (especially enterprise) have countermeasures. I dunno how legit they are but a Google search finds examples claiming a 20 W jammer can cover 500 meters. I'm skeptical that's accurate but it's probably within an order of magnitude. Enough to cover a house, and a large transmitter would plausibly be able to block out a larger facility.
- swores 2y ago
  Interesting comment, thanks! Adding a couple of thoughts I had while reading it: - If the criminals' jamming only needs to protect their identity when people look at footage in the future (as opposed to taking offline a large facility's entire network of cameras so that security can't tell where the criminals are in real time) then they could potentially carry the jammer with them, in which case it just needs to be strong enough to block any camera within sight rather than the full building - In addition to scaling the power of a jammer to take out a big enough area, they could place multiple jammers around the location, either to combine to a larger area or to expand on your directional antenna idea to target individual networked items (cameras, routers, whatever). Even if having many of them means there isn't time to collect them all again when leaving, assuming the crime's pay-off is significant then it could easily still be cost-effective to consider them single use jammers (I'm assuming it wouldn't be hard for people smart enough to plan this sort of crime to make sure that the left-behind jammers can't be traced back to them as an easy solve for the police).
  - gh02t 2y ago
    Yeah hand carryable jammers are a thing you can find them for sale easily which kinda blows my mind considering there's (AFAIK) no legal use for them, nor even any grey area semi-valid use. Granted I've never bought one so maybe all the stores in Google results are fake but I doubt it. Jammers also aren't super expensive and don't need to be supervised, it's entirely possible a thief could just leave a big one in a trash can or something and then abandon it. All that said though I don't think this is a credible threat against anywhere with minimum legitimate security. Everything should be hardwired and battery backed up in any reasonable security system. It's mostly a thing that would effect cheap residential systems.
    - swores 2y ago
      Is it maybe legal to jam wifi signals if either a) your jamming is restricted to inside your private building, with absolutely no leakage outside, or b) the same except regarding property lines rather than physical walls (e.g. if you had a weak jammer in the middle of your private field, whose jamming signals were undetectable at each edge of the field)? My guess would be that A is legal and B might not be, but I've never had reason to look up the relevant laws and I don't know if it would be the same in different countries either. But yeah, I doubt most purchases of portable jammers are for legal use.
      - gh02t 2y ago
        b) is not legal, people have gotten fined for interfering with RF signals on their own property (e.g. stores, restaurants etc). People interfering with GPS or cellular on their own property is also common and highly illegal, and I assume the same laws would apply to wifi. Problem is you can't stop RF propagating off your property lines in that scenario, and noise jamming in the wifi bands can effect other more sensitive equipment that operate in the same bands. But like most things FCC related, you can likely get away with it if you aren't egregious. a) I've never been quite sure. People do testing in Faraday cages so there has to be some exception. I'm pretty sure as long as you aren't interfering externally and are being responsible nobody is gonna fine you.
    - 2y ago

gh02t 2y ago

> The dumping of energy into noise in bands variants tend to be very short ranged because of physics. Sure, but compliant Wifi devices use miniscule transmit power. If you're a criminal you can easily hook up a car battery/generator to a 1000 W transmitter and cover a pretty wide area, or use a directional antenna to focus it a bit more on your target. These sorts of jammers definitely exist, too. Downside though is you're also lighting a huge beacon that says "HELLO I AM DOING SOMETHING ILLEGAL", so you will not be able to keep it up forever. Protocol-based attacks are more discrete, but newer APs (especially enterprise) have countermeasures. I dunno how legit they are but a Google search finds examples claiming a 20 W jammer can cover 500 meters. I'm skeptical that's accurate but it's probably within an order of magnitude. Enough to cover a house, and a large transmitter would plausibly be able to block out a larger facility.

swores 2y ago
Interesting comment, thanks! Adding a couple of thoughts I had while reading it: - If the criminals' jamming only needs to protect their identity when people look at footage in the future (as opposed to taking offline a large facility's entire network of cameras so that security can't tell where the criminals are in real time) then they could potentially carry the jammer with them, in which case it just needs to be strong enough to block any camera within sight rather than the full building - In addition to scaling the power of a jammer to take out a big enough area, they could place multiple jammers around the location, either to combine to a larger area or to expand on your directional antenna idea to target individual networked items (cameras, routers, whatever). Even if having many of them means there isn't time to collect them all again when leaving, assuming the crime's pay-off is significant then it could easily still be cost-effective to consider them single use jammers (I'm assuming it wouldn't be hard for people smart enough to plan this sort of crime to make sure that the left-behind jammers can't be traced back to them as an easy solve for the police).
- gh02t 2y ago
  Yeah hand carryable jammers are a thing you can find them for sale easily which kinda blows my mind considering there's (AFAIK) no legal use for them, nor even any grey area semi-valid use. Granted I've never bought one so maybe all the stores in Google results are fake but I doubt it. Jammers also aren't super expensive and don't need to be supervised, it's entirely possible a thief could just leave a big one in a trash can or something and then abandon it. All that said though I don't think this is a credible threat against anywhere with minimum legitimate security. Everything should be hardwired and battery backed up in any reasonable security system. It's mostly a thing that would effect cheap residential systems.
  - swores 2y ago
    Is it maybe legal to jam wifi signals if either a) your jamming is restricted to inside your private building, with absolutely no leakage outside, or b) the same except regarding property lines rather than physical walls (e.g. if you had a weak jammer in the middle of your private field, whose jamming signals were undetectable at each edge of the field)? My guess would be that A is legal and B might not be, but I've never had reason to look up the relevant laws and I don't know if it would be the same in different countries either. But yeah, I doubt most purchases of portable jammers are for legal use.
    - gh02t 2y ago
      b) is not legal, people have gotten fined for interfering with RF signals on their own property (e.g. stores, restaurants etc). People interfering with GPS or cellular on their own property is also common and highly illegal, and I assume the same laws would apply to wifi. Problem is you can't stop RF propagating off your property lines in that scenario, and noise jamming in the wifi bands can effect other more sensitive equipment that operate in the same bands. But like most things FCC related, you can likely get away with it if you aren't egregious. a) I've never been quite sure. People do testing in Faraday cages so there has to be some exception. I'm pretty sure as long as you aren't interfering externally and are being responsible nobody is gonna fine you.
  - 2y ago