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!"

WAPs + Airport

[francism]

So I should put big, bulky Duck Tape over my beautiful Airport Base Station? No way! Plus, I get poor enough reception in some parts of my own house, never mind my neighbors spying on me. ;-)

I'll take that risk.

[Corpset]

I imagine it would need a lot of things to actually monitor my leds so I'm not worried. Plus, I like too look at them and I won't let them take that away from me :)

Yikes...

[mystery_bowler]

At one time I worked with what I thought was a highly paranoid CIO for a manufacturing company. He had custom-made black plastic covers made for every modem in the modem pool (this was waaaay back) for this very reason.

I tried not to think about it but he was convinced that eventually someone would create technology that would re-construct the data transmission based on those LEDs.

If he's reading this (and he knows who he is), you paranoid sod, damn you for being right. *grin*

reminds me of Cryptonomicon

[Fraize]

...where the main character, in fear of his computer being Van Eck phreaked, redirects output from a decryption program to turn on-and-off his scroll-lock key in morse-code.

Re:Yikes...

[DiveX]

"custom-made black plastic covers made for every modem"

You mean electrical tape?

arrch!

[digitalsushi]

ibm defaced my slashdot page! :'(

Actually

[Corby911]

It makes quite a bit of sense if you think about it. Audiophiles have been using optical output for years (essentially just an LED and a bit of fiber optic cable). What really caught me off gaurd was the distance they were able to capture the data from. Apparently for some, they found they could capture data from "at least across the street".

Almost makes me wish someone cared enough to spy on me so I could prevent it (Duct tape to the rescue!).

Beez

Das Blinkenlights

[mrneutron]

I knew I should have heeded this warning:

ACHTUNG! Alles touristen und non-technischen peepers!
Das machine control is nicht fur gerfinger-poken und mittengrabben. Oderwise is easy schnappen der springenwerk, blowen fuse, und poppencorken mit spitzensparken.

Der machine is diggen by experten only. Is nicht fur geverken by das dummkopfen. Das rubbernecken sightseenen keepen das cotten picken hands in das pockets, so relaxen und watchen das blinkenlights.

Fixing this issue

[pudge_lightyear]

I'll just put my modem upside down...that way, everything will transmit backwards...

Re:LED Mods

[Maran]

Yeah, but then you get some wag at the manufacturer who programs the LEDs to make it seem as if you spend your entire time looking at porn, downloading strange software and sharing your semi-legal files with other geeks.

(Remembers where he's posting)

Never mind!

Maran

A quick solution

[smaughster]

Just hide your hub in a teddy bear, noone will point his eavesdropping device on such an innocent toy, would they?

Thanks slashdot moderators

[Anonymous Coward]

For modifying someone's unsubstantiated "hunch" as informative.

I've seen my lights blink, and I don't think that there's any way
Yes, and I've looked on a CD and I just don't see any data on it.

Re:LED Mods

[JPriest]

I wonder where I can get an LED mod that fakes my downloading of the DMV's database. It'll be cool when they take my HDD and horde my pr0n instead.

Re:ummm...doubtful

[Anonymous Coward]

You should be in the Guiness book of world records. You apparently have the ability to see lights blinking or modulate at rates in excess of 100 hz.

Going to the movies must be pretty tough on you. Watching all that blank time between frames must be pretty nerve racking. I can't even imagine how terrible television appears to you.

If you read the paper, it is based on some pretty coherent testing and past work by others. I think there would be some peer review before publication of an article. But since you have weighed in with your amazing visual prowess, they should just toss out the guy's work.

I know how he feels.

[Anonymous Coward]

That funny. I to sometimes think that if I stare at those blinking lights long enough I would be able to discern a message. I just chalked it up to my familys history of mental illness. But it turns out I was right all along.

Re:Just a guess...

[VoiceOfRaisin]

When the light is ON, the data is "1"
When the light is off, the data is "0"

I guess that modem in my closet is receiving a lot of 0s then

Ok...

[Psmylie]

I'll get right on that, as soon as I finish my tinfoil hat.

Good lord.

Re:I know how he feels.

[Snowfox]

That funny. I to sometimes think that if I stare at those blinking lights long enough I would be able to discern a message. I just chalked it up to my familys history of mental illness.

But it turns out I was right all along.

Don't be so sure. We're all commenting on a kernel update story. What are you seeing!?

Cheap backup solution!

[JMZero]

I can backup the whole network by videotaping the front panel of our switch.

.

The horror!

[stinky wizzleteats]

First they take away my command line and replace it with windoze. Then they take away my sexy jet-engnine-spin-up sounding RLL and MFM hard drives. And now no blinky lights?!

Sure, I can leave behind the days where troubleshooting Ethernet required a resistance meter, and when you could hear the memory counting up, and when a goddammed power switch was a goddammed power switch, but now I have to give up blinky lights? What is the world coming to where a computer geek can't proudly behold his array of blinky lights!?

Where's the joy? These evil led sniffing bastards simply must be stopped, that's all there is to it. I'll 3DES the signal going to the LEDs before I resort to covering my beloved LEDs. Duck tape be damned.

Re:Das Blinkenlights

[getagrip]

Here is the babelfish translation:

NOTE! All tourist and non technical peepers! The machine control is not fur gerfinger poken and mittengrabben. Oderwise is easy snatch that branching factory, blowen fuse, and poppencorken with sharpen-deactivate. The machine is by experts diggen only. Is fur do not geverken by the dummkopfen. Rubbernecken sightseenen keepen the that cotten picken hands in pockets, then relaxen and watchen blinkenlights.

Re:A quick solution

[Happy Monkey]

As I stare intently into the glowing eyes of your bear, I can almost make out a message...

Simple Solution to LED Problem (tinfoil breach)

[Charlie Bill]

1) Remove tinfoil from head. This will allow the FBI to read your thoughts and aliens to control your thinking, but this is LED SECURITY!!
2) Place tinfoil over LED (a) at a 45-degree angle reflecting the light towards LED(b). Poke a hole in the tinfoil to allow some light through.
3) Take tinfoil and make covering/receiving/reflecting receptor on LED(b).

When LED(a) lights, any scanning devices will be mercilessly confused by the colighting of LED(b). The secret bat equipment will be useless!

4) Make sure you put tinfoil back on head.

I do this already

[AgentTim3]

Yeah, that's right. I just head into the server room, turn all the lights out, and stare at the routers.

Sure, it takes awhile to learn how to read it...

But after awhile, I just see Blonde here, Brunette there, Redhead over there...

Re:Thanks slashdot moderators

[RandomPeon]

Yeah, I picked up the phone while somebody was using a modem. I didn't hear any of the webpage they were downloading, just noise. Random-sounding noise that always sounded random.

Re:Yikes...

[pboulang]

I tried an internal modem once, but it hurt when I walked.