4 ms·

Then why does it switch heavy loads if it shouldn't do that?

stavros 3y ago
Because someone unauthorized used a device to force it to do that. These devices are not built to be operated by the general public. Anyone who operates these devices knows to reduce the load first. I don't see the sense in saying "these devices, built for a specific industry with specific, exacting specs, should instead have been built with different specs that were never meant to occur". Everywhere in industry we train operators to know how to operate machinery that can be made to break itself, because it's cheaper to train the operator than to make the machine unable to break itself.
- Dylan16807 3y ago
  When I press the power button on my remote, I ain't "forcing" anything.
  - stavros 3y ago
    You have a remote to your smart meter? Or are you talking about an entirely different device?
    - Dylan16807 3y ago
      Do you think the type of device matters? The remote sends a signal to the chip in the device, and that chip decides what to do, often ignoring the signal if it's currently busy or otherwise doesn't want to. There is no force here. Even if it wants to turn off on request in case of dangerous external circumstances, it doesn't need to turn back on so easily and rapidly.
      - stavros 3y ago
        Yes, I think it matters whether it's a consumer device or specialized equipment that will be handled by trained operators. You're looking at a $500K farming tractor and complaining that it doesn't have collision avoidance.
        deleted 3y ago
        [deleted]
        Ekaros 3y ago
        I would probably expect a collision avoidance in ultra-modern farming tractor. Or at least it to monitor what is in front and stop if clearly unexpected object would be in the path. They are nearly self-driving anyway. And critical failure is expensive in many ways. Now, smart meter being able to shut power off is somewhat expected. But I would also expect it to be protected command.
- atoav 3y ago
  Yeah, but you know why load breakers are usually in electrical rooms with a lock on them? Because that is one of the mechanisms used to ensure only authorized personal is doing the switching. Guess where you don't have that? When you accept inputs via radio. The least you could do then is rate limit the input, better even would be authentication. This doesn't even has to be misuse. It could just be some wonky device sending the "wrong" sequence of zeros and ones on the right frequency and boom. Guarding against this kind of interference is totally the task of the manufacturer. Designing the device in such a way, that you cannot turn a load switch into a makeshift dimmer for a short moment as well.
- Ekaros 3y ago
  Also they do work for occasional switch of under heavy load. And occasional here being in order of once a year rate at most frequent. Still, maybe they should have better security. Specially as there is radio interface.
  - stavros 3y ago
    Yep, definitely agreed on the security aspect.
- mtlmtlmtlmtl 3y ago
  >Because someone unauthorized used a device to force it to do that. Seriously? The device has no authentication. By the design, anyone within range is authorised. And it wasn't "forced". There's no code execution here. It was sent commands, it accepted them. And comparing it to industrial applications with trained workers is just absurd. This is not some hugely complicated industrial system. I really don't see how logic for designing heavy machinery for industrial applications can be uncritically applied to consumer devices. It's just a different space, with different requirements and it's much less complicated.
  - dwaite 3y ago
    > Seriously? The device has no authentication. By the design, anyone within range is authorised. Citation?
- amluto 3y ago
  > Anyone who operates these devices knows to reduce the load first. How? This is a system for remotely opening a circuit. The user can’t reduce the load first. At best they can (likely with too much latency to be at all reliable) wait for the meter to report a small load.
  - diydsp 3y ago
    By remote is meant only a few feet. The intended user can switch off or unplug the load in person then operate the meter.
    - krisoft 3y ago
      > By remote is meant only a few feet. How does it enforce that? Is it just based on signal strength? > The intended user can switch off or unplug the load in person then operate the meter. This is just the wrong way to think about it. The "intended user" is all nice, but what can an attacker do? That is how these problems need to be analysed.
    - amluto 3y ago
      I regret to inform you that remote means from the office. These meters use a mesh network to report usage and receive instructions from the utility’s central systems. If a technician were on site, they could physically remove the meter or open the main breaker.

Because someone unauthorized used a device to force it to do that. These devices are not built to be operated by the general public. Anyone who operates these devices knows to reduce the load first. I don't see the sense in saying "these devices, built for a specific industry with specific, exacting specs, should instead have been built with different specs that were never meant to occur". Everywhere in industry we train operators to know how to operate machinery that can be made to break itself, because it's cheaper to train the operator than to make the machine unable to break itself.

Dylan16807 3y ago
When I press the power button on my remote, I ain't "forcing" anything.
- stavros 3y ago
  You have a remote to your smart meter? Or are you talking about an entirely different device?
  - Dylan16807 3y ago
    Do you think the type of device matters? The remote sends a signal to the chip in the device, and that chip decides what to do, often ignoring the signal if it's currently busy or otherwise doesn't want to. There is no force here. Even if it wants to turn off on request in case of dangerous external circumstances, it doesn't need to turn back on so easily and rapidly.
    - stavros 3y ago
      Yes, I think it matters whether it's a consumer device or specialized equipment that will be handled by trained operators. You're looking at a $500K farming tractor and complaining that it doesn't have collision avoidance.
      - deleted 3y ago
        [deleted]
      - Ekaros 3y ago
        I would probably expect a collision avoidance in ultra-modern farming tractor. Or at least it to monitor what is in front and stop if clearly unexpected object would be in the path. They are nearly self-driving anyway. And critical failure is expensive in many ways. Now, smart meter being able to shut power off is somewhat expected. But I would also expect it to be protected command.
atoav 3y ago
Yeah, but you know why load breakers are usually in electrical rooms with a lock on them? Because that is one of the mechanisms used to ensure only authorized personal is doing the switching. Guess where you don't have that? When you accept inputs via radio. The least you could do then is rate limit the input, better even would be authentication. This doesn't even has to be misuse. It could just be some wonky device sending the "wrong" sequence of zeros and ones on the right frequency and boom. Guarding against this kind of interference is totally the task of the manufacturer. Designing the device in such a way, that you cannot turn a load switch into a makeshift dimmer for a short moment as well.
Ekaros 3y ago
Also they do work for occasional switch of under heavy load. And occasional here being in order of once a year rate at most frequent. Still, maybe they should have better security. Specially as there is radio interface.
- stavros 3y ago
  Yep, definitely agreed on the security aspect.
mtlmtlmtlmtl 3y ago
>Because someone unauthorized used a device to force it to do that. Seriously? The device has no authentication. By the design, anyone within range is authorised. And it wasn't "forced". There's no code execution here. It was sent commands, it accepted them. And comparing it to industrial applications with trained workers is just absurd. This is not some hugely complicated industrial system. I really don't see how logic for designing heavy machinery for industrial applications can be uncritically applied to consumer devices. It's just a different space, with different requirements and it's much less complicated.
- dwaite 3y ago
  > Seriously? The device has no authentication. By the design, anyone within range is authorised. Citation?
amluto 3y ago
> Anyone who operates these devices knows to reduce the load first. How? This is a system for remotely opening a circuit. The user can’t reduce the load first. At best they can (likely with too much latency to be at all reliable) wait for the meter to report a small load.
- diydsp 3y ago
  By remote is meant only a few feet. The intended user can switch off or unplug the load in person then operate the meter.
  - krisoft 3y ago
    > By remote is meant only a few feet. How does it enforce that? Is it just based on signal strength? > The intended user can switch off or unplug the load in person then operate the meter. This is just the wrong way to think about it. The "intended user" is all nice, but what can an attacker do? That is how these problems need to be analysed.
  - amluto 3y ago
    I regret to inform you that remote means from the office. These meters use a mesh network to report usage and receive instructions from the utility’s central systems. If a technician were on site, they could physically remove the meter or open the main breaker.