LED Lights: Friend or Foe?

elfdump writes: "In an article (pdf) soon to be published in ACM Transactions on Information and Systems Security, security researchers have discovered that data transmitted through modems and routers can be remotely reconstructed from the equipment's LED status indicators. According to experiments, their light-to-information retrieval method is successful even when the light is captured 'at a considerable distance' from the source. If you want to prevent people from spying on your data, you may want to tape up those blinking LEDs!"

Comments

This is BEYOND dumb.

[geekboy_x]

The lights on your modem or switch do NOT pulse everytime that a 1 or a 0 gets sent down the pipe. In the case of a modem, they pulse whenever the controller sends a request to the UART. In between those requests, a WHOLE HONKING PACKET OF DATA IS SENT. Same with a switch - light comes on when a PACKET IS SENT.

Sheesh - think about it for a second. If the light blinked every time the device passed a 1 or a 0 down the pipe, then either your device would be talking about about 10 bits per second (yawn) or the light would be on full time.

Oh, bullshit

[osgeek]

This is crap. I worked for a router/hub manufacturer, and those guys don't flash the LED every time a bit passes by. They usually flash it every so often, if a packet has gone by. Note the word "packet". There's no conceivable reason why you'd want to waste your very valuable embedded processor time breaking down packets into bytes and bits to make the LED flash more accurately.

What do you learn by even seeing a flash every time a packet goes by?

I'd really doubt that any HW manufacturer is stupid enough to flash an LED every time a bit passes.

Then, you also need to be able to consider the response characteristics of LEDs. Most IR transmissions systems are decidedly limited in the bandwidth that they can pump through, and that's in a system dedicated to pumping it through. I'd highly doubt that the lower-quality LEDs used for displaying packet movement would be capable of keeping up with your average 100Mbps router.

This thing must be an early April Fool's joke.

You can now take the little aluminum hat off your hub.