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donkeycorpse

join:2012-11-18
Schenectady, NY

TEMPEST Attacks! LCD Monitor leaks system noise to FRS

This is a long, but educational read.

I ask DSLReports members to please post their replies to this thread in response to it if anyone here has any answer(s) to solve the problem described in the post.

Thank you.

TEMPEST Attacks! LCD Monitor leaks system noise to FRS
====================
I don't operate any wireless equipment at my living location. This includes computers, computer equipment, routers, non-computer equipment, etc.

I'm having a problem with one of my LCD monitors.

It works without problems. That was until I picked up some heavy static noises from a hand held radio. I eliminated all sources of generating this type of noise until I came towards an LCD monitor. When the monitor is on and there is content on the screen the radio makes several types of garbage(static) sounds. As I manipulate contents on the screen, maximize and minimize windows, open different applications, the radio responds with scratchy(static) noises to match the activity on the screen. This includes typing and mouse movement.

When I switched the desktop background to a solid black color without wallpaper, the radio noise went down to almost nothing. But when I loaded any program with a white background, the noise from the radio exploded in volume.

When I passed the radio across different computer and non-computer electronic devices other than the LCD monitor, the wired mouse made a high pitched squeal sound within the static. None of the other computing devices such as the tower generated any noise.

I tried CRT monitors and separate computers attached to the CRT monitors but they did not generate any noise in the radio. On the computer connected to the net, I unplugged the cable leading to the router to rule this out but it made no difference, the LCD monitor is at fault.

While monitoring the radio noise, there were several instances where the noise on the channel being monitored stopped, and I switched to another channel and the same noise appeared. Why would the noise from the LCD switch channels during normal use of the LCD? Back and forth throughout the day the noise generated by the LCD would switch from one channel to the next and back to the first channel again.

The noise extends several steps within my living location. I'll test this another day to determine if it extends outside my living location and if so by how many feet.

The computer/monitor are grounded and attached to a surge protector. I'm not sure what I need to do to stop this, or if I should ignore it.

I assumed LCDs would be quieter than CRTs when it came to noise.

Unless I have a radio tuned to a specific channel, the LCD does not generate any noise which I can detect, unless it's above my hearing capacity.

The LCD monitor also functions as speakers, and while the sound cable is connected to the tower, I have disabled the onboard sound in my BIOS. The only other connection is the DVI cable to the tower.

How may I decrease this noise or eliminate it? It seems like the LCD is a mini radio station. When I turn it off the noise in the radio stops, if I blacken the screen the noise lessens. When I switch to a colorful background or load white screened applications like a web browser the noise jumps up loudly. I've tried grabbing and moving a browser window around the screen and the movement matches the noises in the radio.

Would any of this be considered normal?
========================================
This certainly isn't unheard of, it's because some part of the monitor is unshielded. The more fix-it stuff is at the top of the following, with the technical backdrop that just might be good to know is at the bottom.

Unfortunately, the issue is most likely the panel charging the LCs. The only thing you can do is see if the manufacturer will replace it or upgrade you. Complain to the manufacturer, be sure to come up with some important thing it's interfering with(if I recall some medical devices use some sort of radio).

If the issue is actually internal wiring which is highly unlikely as detailed below, and it isn't in warranty, attempt to shield it yourself. To shield it yourself, you'll need thin foil(not kitchen foil) and electrical tape.

So, in any given monitor, there's 3 main parts. Input, logic, and output. Output, as previously mentioned, can't really be shielded. To shield both of the other sections, all you really need to do is manipulate the wiring to reduce the number of holes in the foil wrap needed to put it all back together. Obviously this will take some trial and error, and time.

USEFUL INFO THAT ISN'T REQUIRED:

Shielding wires can best be thought of as a encasing a wire in a Faraday cage, made of foil. If you want to see an example, Apple's iPod charging cords are all shielded, strip the insulation and see for yourself. This shielding acts doubly, keeping EM noise from messing with the signal, and keeps the signal's own noise from leaving.

WHY IT IS THE CHARGING PANEL AND NOT WIRING:
Because of the specific details you provided( bravo to you, the amount of data provided helped ), I can conclude that the charging panel(the array of electrodes responsible for producing the image) is putting out the interference. Three of your observations prove this.

First, you state the noise ceases completely when the monitor is turned off, which is consistent with it being EM noise.
Second, the noise's perceived pitch changes when the display is manipulated, which is to be expected, as the electrode charges would change as the display changes.
Third, a black screen is "quieter" than a white screen. Black is the lowest charge state, with the only power in use going to the backlight.

As for your questions:
Noise hopping channels isn't unheard of, though I don't know the science behind it. My best guess is that because the noise isn't an intended result of the electricity, small changes in voltage/amperage result in those hops.
(indirect question-ish) The mouse was likely the only other emitter because it has a fairly high density of wires + it emits light.
=====================
@W00t:

What 1s the d1fference between - and where may 1 obta1n the non-k1tchen "foil" you ment1oned?

The d1sturbances sound l1ke a bugged env1ronment. The squeal com1ng from one area and/or dev1ce could mean the locat1on of the bug has been found - and 1 know adding a small dev1ce and/or mod1f1cation to a keyboard and/or mouse 1s s1mple enough - espec1ally for a quick 1n and out the door type bugging.

1s there an affordable method of sh1elding the equ1pment while not violating FCC/TEMPEST laws? Would a simple screen d1mmer attached to the monitor bring the no1se down? Or would 1t be best to put out the extra money requ1red by purchas1ng spec1al paint or wallpaper wh1ch blocks RF signals?

Whether or not 1t's a bug, at this point you are broadcast1ng your computer mon1tor and 1ts activ1t1es, down to the keyboard and mouse movements. What 1s the use of using Tor or any other l1ke serv1ce 1f you are pwned over the a1r waves?
===========================
You could use kitchen foil, it's just more unwieldy to work with.

Yes, it could be a bug, I was running under the assumption you had no reason to believe you were bugged, and if you did you ran bug sweeps. If you believe you are bugged, you should definitely dismantle things to make sure a bug isn't simply piggybacking on the same power source.

Dimming the screen would reduce noise, but not completely eliminate it.
============================
Thanks, W00t.

"Dimming the screen would reduce noise, but not completely eliminate it."

I have modified my browser to function with a black background and my choice of text colors and unchecked the option for all pages to use their own colors, so every page I visit is black with my choice of font/links colors. I'll rescan to determine if this lessens the noise. It's ugly, but tolerable. Coupled with a black theme for the desktop, including the background and system wide applications should also help - including disabling images in the browser.

You mentioned foil. I'm not an electrician, but wouldn't wrapping cords with foil and finishing the job off with a layer of strong black tape possibly conduct electricity? Are you suggesting I cover all wires leading to the computer(s) using this method? Wouldn't they each require special grounding? How many repeating layers of this and/or other material is needed? Have you tried "conductive tubing?"

While I want to shield enough to block noisy RF, I don't want to create a microwave type scenario where RF is contained but it still remains and is possibly amplified so as to add to the degeneration of my health, if that's possible.

1. Ferrite beads
2. Split beads
3. Toroids

CONDUCTIVE TUBING & FERRITE SNAP BEAD
»www.lessemf.com/wiring.html

»en.wikipedia.org/wiki/Electromag···rference
»en.wikipedia.org/wiki/Electromag···d_health
»en.wikipedia.org/wiki/Electromag···hielding
»en.wikipedia.org/wiki/EMF_measurement

I could try some or all of the three options above in addition to your advice? TY
==============
Anyways this reminding me of Van Eck phreaking look it up, some pretty interesting stuff.

Yep, had the same thought.

Countermeasures are detailed in the article on TEMPEST, the NSA's standard on spy-proofing digital equipment. One countermeasure involves shielding the equipment to minimize electromagnetic emissions. Another method, specifically for video information, scrambles the signals such that the image is perceptually undisturbed, but the emissions are harder to reverse engineer into images. Examples of this include low pass filtering fonts and randomizing the least significant bit of the video data information.
=============
can someone please point me to techie LCD monitor internal guides? If I'm going to take it apart I'd like to know what to expect. I've read more about Van Eck and Tempest than anyone can teach me here. Now I'm looking for LCD guides of what's inside.
===========
To be honest, its not the whats inside the LCD monitor you should be worrying about if you want to phreak LCD's . You should be worry more about the RF side of things, and figuring out the spread spectrum clock signal so you can pick up the signal. Top if off background noise is going to be bitch when it comes to LCD. Old CRT monitors are way easier to phreak those thing throw off EM radiation like nobody business.
===========
The noise coming from the LCD monitor is appearing on FRS channels:

- »en.wikipedia.org/wiki/Family_Radio_Service

It continues for several minutes before it jumps to another channel then after a few minutes jumps back to the original channel. One of my concerns is the ability for others to pluck this noise from the air (Van Eck/TEMPEST) and monitor my activity, or possibly use an attack against the computer somehow. A recent UN report mentioned a high tech method(s):

* U.N. report reveals secret law enforcement techniques

"Point 201: Mentions a new covert communications technique using software defined high frequency radio receivers routed through the computer creating no logs, using no central server and extremely difficult for law enforcement to intercept."

- »www.unodc.org/documents/frontpag···oses.pdf
- »www.hacker10.com/other-computing···hniques/

In addition, I don't want my LCD monitor constantly sending monitor and/or system activity to a FRS channel(s) for others to hear. I choose wired over wireless for a reason, and there shouldn't be any noise coming from my LCD monitor and appearing over FRS, unless there is a bug or problem with the monitor. All of my
CRT systems are silent on FRS.

When I position the radio near different components, the power supply doesn't emit any noise on FRS, but it could be a problem, I don't know, I'll move to that once I resolve the LCD monitor problem, unless the PSU is the problem and not the monitor.

I may take apart the LCD monitor, I'm looking for a good list of what I'll find if I do.

I peered inside the vents on the top/back left hand side with a strong flashlight and came across a strange piece of silver tape inside, here's how I describe it:

OOGGGGGGGGGGGGGGG__

OO = a small thin black material coming out from underneath the silver piece of tape
GG = the strip of silver tape
__ = the bottom right hand portion of the silver tape is raised enough to allow a pinky finger entry

The silver tape/material/opening under tape is on the top left corner inside the monitor. The rest of the length and area inside that I can see contain no tape or black material. I've seen photos of planted bugs in people's living spaces and most if not all of the invasive ones are wrapped/covered in silver foil. I've found no other reason for that strip and material to be there, but what do I know.
=====
In addition, my CDROM drive light blinks once every second, sometimes with a second or 1/2 second in between, and I found this:

»catless.ncl.ac.uk/Risks/19.60.html#subj9

"I'd worry about a Tempest virus that polled a personal computer's
CD-ROM drive to pulse the motor as a signalling method:

* Modern high-speed CD-ROM drive motors are both acoustically and
electrically noisy, giving you two attack methods for the price of one;

* Laptop computer users without CRTs, and the PC users that can afford
large LCD screens instead of CRTs, often have CD-ROM drives;

* Users are getting quite used to sitting patiently while their
CD-ROM drives grind away for no visibly obvious reason (but
that's quite enough about the widespread installs of software from
Microsoft CD-ROMs that prompted Kuhn's investigation in the first place.)"
=======
I don't think there should be anymore blinking if you remove the CD/DVD inside.
If it keeps blinking, find out which process uses it.
Anyway, you can disable it when you're not using it, if it's bothering you.

And shield your monitor.
»en.wikipedia.org/wiki/Electromag···hielding
========
"I don't think there should be anymore blinking if you remove the CD/DVD inside."

Does Tails support this at boot?

If not, is there a Linux LiveCD which allows this and does not give you root access at boot?

I've looked at several different distributions which allow you to boot into RAM and remove the CD, but they all give you root and that's a very insecure environment to run TBB in!

"If it keeps blinking, find out which process uses it."

It doesn't blink on the several distros which boot into RAM, but I don't want to run Tor as root or reconfigure the permissions/PAM/etc. just to use TBB. As above, with Tails and many LiveCDs which don't boot into RAM, 99% of them have this blinking light issue. The actual INSTALLS I've done to HDD experience constant light activity too, even more so, without anything to explain them.

For Linux, I've ran rkhunter, chkrootkit, tiger, and other tools and nothing malicious is found. Without a deep binary analysis I don't know what else I could do.

For Windows, I use a few programs in the SysInternals Suite and they display strange usage on the system and reference programs which cannot be found with a search on the system, references to impersonation, spoofing, and more. I've ran almost every N.American scanner on the Windows systems, including command line only rootkit detectors and I've seen some strange 'strings' of binaries mentioned, but have no idea on how to clean the system.

I prefer to run LiveCDs because all installations, Windows and Linux, contain unexplainable frenzies of blinking lights, far worse than the blink every second on most LiveCDs. I'm wondering if this is firmware malware on my NIC or the CDROM itself. This has existed for years and never goes away, no matter what system I use, this strange baggage seems to re-infect everything.

"Anyway, you can disable it when you're not using it, if it's bothering you."

Disable what?

"And shield your monitor."

Thanks. I'm investigating and most of the guides require specific addons to the computer's cabling system. Most of the guides appear incomplete, or are in another language other than English.

Any comments on the Tempest/blinking light possibility?

Any comments on why it's spewing out noise to FRS stations and freq hopping?
======
More comments from elsewhere:

@kb2vxa:

"You're making a mountain out of a mole hill."

I respect your opinion and I don't wish to argue against it, but please look at it from the way I and some others have. I want to eliminate the noise created by the LCD monitor. If this was such a common experience, I would expect at least one of the dozens of other electronic equipment to generate some noise, however faint, on FRS - but they do not.

"You are under the wrong impression that somehow RF hash from the back light can somehow carry data. A liquid crystal display (LCD) does not generate its own light like a CRT or plasma screen and requires a light source to make the display visible. Even those that do cannot transmit computer data being none reaches the monitor."

The LCD is connected to a tower, which other devices connect to. Under testing I've heard the CDROM drive accessing data noises within the FRS channels, along with mouse movements and keyboard activity, along with other noises. When I disable the LCD monitor, all of these disturbances vanish. This means the weakness is in the monitor, and my tower is well shielded or shielded enough so as not to generate any noise in radios I can notice. The reference I made to the strange tape and material within the back side of the LCD monitor at the top could be a sign of some type of antenna or device for amping.

"Their FRS radios will only hear what yours does, RF hash, no data whatsoever THAT IS if one is standing outside your house tapping the radio and scratching his head wondering what's the matter with his radio. You and only you know what it is and where it's coming from."

And what of experienced and curious sysadmins? Rogue crackers? Bored HAMs?
Are there any remote radio injection attacks against systems? This is something I'll research later, as I do believe it was mentioned in at least one whitepaper on side channel attacks.

"Thanks for the chuckles, if the report reveals secrets it would not be published but sent by secret courier to the KGB in Moscow."

I'm not aware of any secrets revealed within the document. But it did raise an interesting point without exposing the method(s) delivered to us from an interesting party. This wasn't just some random article written by some anonymous, disturbed fellow and posted to a pastebin or conspiracy minded blog or forum. And one cannot deny the dozens of TEMPEST attacks available today.

"So... all this and no word on moving the radio farther from the monitor. Why don't you try talking somewhere besides in front of the computer if it bothers you so much?"

Thank you for considering conversation as my reason for posting this, but it is not. I would not choose a noisy channel to talk on. Clear conversation is not the point of this thread. I desire the elimination of this garbage coming from the LCD monitor. I don't care if no one in the world can pick up on it and hear it, I would like to properly resolve it and not ignore it.

One can also dredge up the subject of EMF on health, too, but I have not experienced any disturbance of health from exposure to this noise and most people would argue any possible EMF effects on health to be one of one's over active imagination and not real world application.

[-]

A continued discussion was posted elsewhere, this may be useful in the voyage to remove this "noise":

[-]

In addition, my CDROM drive light blinks once every second, sometimes with a second or 1/2 second in between, and I found this:

[-]

»catless.ncl.ac.uk/Risks/19.60.html#subj9

"I'd worry about a Tempest virus that polled a personal computer's
CD-ROM drive to pulse the motor as a signalling method:

* Modern high-speed CD-ROM drive motors are both acoustically and
electrically noisy, giving you two attack methods for the price of one;

* Laptop computer users without CRTs, and the PC users that can afford
large LCD screens instead of CRTs, often have CD-ROM drives;

* Users are getting quite used to sitting patiently while their
CD-ROM drives grind away for no visibly obvious reason (but
that's quite enough about the widespread installs of software from
Microsoft CD-ROMs that prompted Kuhn's investigation in the first place.)"

[-]

Any comments on the silver tape and material inside the back of the LCD?

...Disconnection of the LED CDROM and HDD lights could be something I should do to relieve one possible issue.

[-]

Some articles with examples:

"If everything is just right, you can pick up signals from some distance. "I was able to eavesdrop certain laptops through three walls," says Kuhn. "At the CEBIT conference, in 2006, I was able to see the Powerpoint presentation from a stand 25 metres away."

uhn also mentioned that one laptop was vulnerable because it had metal hinges that carried the signal of the display cable. I asked if you could alter a device to make it easier to spy on. "There are a lot of innocuous modifications you can make to maximise the chance of getting a good signal," he told me. For example, adding small pieces of wire or cable to a display could make a big difference.

As for defending against this kind of attack, Kuhn says using well-shielded cables, certain combinations of colours and making everything a little fuzzy all work."

- »www.newscientist.com/blog/techno···lls.html

=!========================================!=
TO EASILY VIEW THE PDF files below:
=!========================================!=

Online viewer for PDF, PostScript and Word:

"This is an online viewer, with which you can view PDF and PostScript files as browsable images and Word documents as web pages. Given a URL on the net or a file on your computer, the viewer will try to retrieve the document, convert it and show it to you. No plugin software is required."

»view.samurajdata.se/

The viewer software is open source, licensed under the GNU Public License.
=!========================================!=

Electromagnetic eavesdropping risks of flat-panel displays
»www.cl.cam.ac.uk/~mgk25/pet2004-fpd.pdf

=

Eavesdropping attacks on computer displays
- »www.cl.cam.ac.uk/~mgk25/iss2006-tempest.pdf

=

Compromising emanations: eavesdropping risks of computer displays
- »www.cl.cam.ac.uk/techreports/UCA···577.html
- »www.cl.cam.ac.uk/techreports/UCA···-577.pdf

=

Compromising emanations of LCD TV sets
- »www.cl.cam.ac.uk/~mgk25/emc2011-tv.pdf

=

"Q: Can I use filtered fonts also on flat-panel displays

My experience so far has been that with LCDs, the video cable is the most significant source of radiated information leakage. Where an analogue video cable (with 15-pin VGA connector) is used, low-pass filtered fonts have the same benefits as with CRTs. Where a purely digital video cable is used (DVI-D, laptop-internal displays with FPD/LVDS links, etc.) only the last step, namely randomizing the least-significant bits, should be implemented.

Where the video signal is entirely encoded in digital form, the low-pass filtered step will not have the desired effect. In fact, it can actually increase the differences between the signal generated by individual characters, and thereby make automatic radio character recognition more reliable."

- »www.cl.cam.ac.uk/~mgk25/emsec/so···faq.html

=

Remotely Eavesdropping on Keyboards (and read the comments!)

"The researchers from the Security and Cryptography Laboratory at Ecole Polytechnique Federale de Lausanne are able to capture keystrokes by monitoring the electromagnetic radiation of PS/2, universal serial bus, or laptop keyboards. They've outline four separate attack methods, some that work at a distance of as much as 65 feet from the target.

In one video demonstration, researchers Martin Vuagnoux and Sylvain Pasini sniff out the the keystrokes typed into a standard keyboard using a large antenna that's about 20 to 30 feet away in an adjacent room."

- »www.schneier.com/blog/archives/2···esd.html

=

Video eavesdropping demo at CeBIT 2006
- »www.lightbluetouchpaper.org/2006···it-2006/

=

Optical Emission Security – Frequently Asked Questions

"Q: What about LEDs?

For devices with RS-232 serial ports, it is customary to provide a status indicator LED for some of the signal lines (in particular transmit data and receive data). Often, these LEDs are directly connected to the line via just a resistor. As a result, anyone with a line of sight to the LED, some optics and a simple photosensor can see the data stream. Joe Loughry and David A. Umphress have recently announced a detailed study (submitted to ACM Transactions on Information and System Security) in which they tested 39 communications devices with 164 LED indicators, and on 14 of the tested devices they found serial port data in the LED light. Based on their findings, it seems reasonable to conclude that LEDs for RS-232 ports are most likely carrying the data signal today, whereas LEDs on high-speed data links (LANs, harddisk) do not. Even these LEDs are still available as a covert channel for malicious software that actively tries to transmit data optically.

I expect that this paper will cause a number of modem manufacturers to add a little pulse stretcher (monostable multivibrator) to the LEDs in the next chip set revision, and that at some facilities with particular security concerns, the relevant LEDs will be removed or covered with black tape.

The data traffic on LEDs is not a periodic signal, and therefore, unlike with video signals, periodic averaging cannot be used to improve the signal-to-noise ratio. The shot-noise limit estimation technique that I used to estimate the CRT eavesdropping risk can even more easily (because no deconvolution is needed) also be applied to serial port indicators and allows us to estimate a lower bound for the bit-error rate at a given distance. I have performed a few example calculations and concluded that with a direct line of sight, and a 100 kbit/s signal (typical for an external telephone modem), at 500 m distance it should be no problem to acquire a reliable signal (one wrong bit every 10 megabit), whereas for indirect reflection from the wall of a dark room, a somewhat more noisy signal (at least one wrong bit per 10 kilobit) can be expected to be receivable in a few tens of meters distance.

- »www.cl.cam.ac.uk/~mgk25/emsec/op···faq.html

=

Ancient Story on Slashdot: Coming to a Desktop near you: Tempest Capabilities

"New Scientist has an interesting article about a new toy we will all want. It's a card that plugs in one of your PCI slots and allows you to scan the EMF spectrum and read your neighbours terminal. In about 5 years you might be able to get one for just under £1000. (Modern Tempest Hardware costs about £30000) "

»www.yro.slashdot.org/story/99/11···bilities

=

"Any unshielded electrical device with a variable current (including LCDs) will give out EMF radiation. It's the nature of the beast.

For that matter, light is EMF radiation, so unless you have your LCD in a coal-mine, it's reflecting EMF all the time it's switched on.

Then, there's the fact that screen monitoring isn't the only monitoring you can do. I used to use a radio, tuned into the bus for the PET, as a sound card. Worked surprisingly well, for all that very clunky metal shielding. What's to stop a much higher-quality receiver from seeing the data, in an unshielded box, being sent TO the LCD, or to any other device on the machine?

It's a mistake to assume that Tempest technology is single-function and that that single-function only works in a single situation."

- »slashdot.org/comments.pl?sid=233···=1553178

=

800Mbps Wireless Network Made With LED Light Bulbs
- »science.slashdot.org/story/11/08···ht-Bulbs

=

There are a lot of other files, many in PPT format, which can be found easily on this subject of LCD monitor (and other computing devices) TEMPEST sniffing.

================================================================================== =======

Sources for this discussion:

- »forums.radioreference.com/comput···why.html
- »clsvtzwzdgzkjda7.onion/viewtopic···&t=10919

.onion link above requires a running Tor client session in order to view. (»www.torproject.org)

This on-going discussion backed up to Pastebin(s) in order to retain it as an artifact. Many of these
types of discussions are REMOVED from the net because of the nature of the discussion (TEMPEST).


Elite

join:2002-10-03
Orange, CT

1 recommendation

This is a long mess of shit, contrived by a nutcase.

The NSA would rather just wiretap your ISP (AT&T?)

Edit: Tor link at the bottom takes the cake.
--
QUAD!!!!



norwegian
Premium
join:2005-02-15
Outback
reply to donkeycorpse


First is sounds like the electronic noise suppression in the LCD monitor isn't working, very basic electronic requirement of all electronic devices. Request the LCD be RMA'd.

Secondly the foil inside the monitor is actually earth straps across the differing items/boards, mini-boards and components. This is a general hardware/electronics question any electronics engineer will supply answers for.

I'm with Elite on this, there are far more easier ways to track you, including a hand held SAT dish to pick up all your conversations from a vehicle outside your house if 3 letter agencies wanted your daily routines.

--
The only thing necessary for the triumph of evil is for good men to do nothing - Edmund Burke



Raphion

join:2000-10-14
Samsara

1 recommendation

reply to donkeycorpse

Bottom line; So long as you exist in this world, you can be monitored.



Name Game
Premium
join:2002-07-07
Grand Rapids, MI
kudos:7

1 recommendation

reply to donkeycorpse

»TEMPEST ATTACK MYTH

Merry Christmas



rcdailey
Dragoonfly
Premium
join:2005-03-29
Rialto, CA
Reviews:
·Time Warner Cable

Gee, I remember TEMPEST from the 1960s, before the internet or personal computers. I guess the most notorious episode involved the original IBM Selectric typewriter. My recollection is that those typewriters were not to be used to prepare classified documents, at least after the issue was identified. Maybe they were overcautious about that based on looking at what is on line about the subject today.
--
It is easier for a camel to put on a bikini than an old man to thread a needle.


Secyurityet

join:2012-01-07
untied state
reply to donkeycorpse

If the experts were worried about this, the building where I work wouldn't have a single LCD monitor in it.



jimkyle
Btrieve Guy
Premium
join:2002-10-20
Oklahoma City, OK
kudos:2
Reviews:
·AT&T Southwest

I don't operate any wireless equipment at my living location. This includes computers, computer equipment, routers, non-computer equipment, etc.

No electric clocks, HVAC thermostats, CFL light bulbs, electric stoves, or microwave ovens, not to mention TV sets and radios? If it uses electricity at all, it can radiate RF energy that can be detected at close range...
--
Jim Kyle


La Luna
Survived Ashraful
Premium
join:2001-07-12
Warwick, NY
kudos:3
reply to donkeycorpse

I can't even read that. My eyes man, my eyes!!!

Can anyone roll this into a nutshell in one paragraph?



Name Game
Premium
join:2002-07-07
Grand Rapids, MI
kudos:7

Don't eat yellow snow when you are using your computer or laptop in the walk-in beer cooler to prevent a Tempest Attack and keep your empties in there until the half life decay is up... it is understood that the rest of us will be "vulnerable"..but we are taking pills of it.



La Luna
Survived Ashraful
Premium
join:2001-07-12
Warwick, NY
kudos:3

Ahh, well that explains it.



StuartMW
Who Is John Galt?
Premium
join:2000-08-06
Galt's Gulch
kudos:2

1 edit
reply to donkeycorpse

Bob can see what's on my LCD monitor(s)? Just wait until I finish my Faraday cage

At least we don't have TV licensing in the US (and the vans that roam the streets looking for unlicensed TV's).


--
Don't feed trolls--it only makes them grow!



Warzau
Premium
join:2000-10-26
Naperville, IL
kudos:1
reply to donkeycorpse

I prefer this Tempest »www.gamesloon.com/free-arcade-3/···816.html



StuartMW
Who Is John Galt?
Premium
join:2000-08-06
Galt's Gulch
kudos:2
reply to norwegian

said by norwegian:

Secondly the foil inside the monitor is actually earth straps across the differing items/boards, mini-boards and components. This is a general hardware/electronics question any electronics engineer will supply answers for.

As an EE I'll answer this one.

In the US, Europe and other countries the emissions (radio waves) of electronic devices must be under a certain level. The foil you see inside many devices is to reduce these emissions and/or prevent them being affected by external signals (shielding).

Many of the products I've designed over the years have had to go through EMC labs to ensure that they meet FCC (US) and CE (Europe) requirements. It is actually an unpleasant experience to see what these labs do to your "baby" (design) in an attempt to fail you and/or destroy it.

Upon returning from a day at "the lab" my boss and coworkers would often gather around and ask how things went. Just like they would if you have a sick relative in the hospital.
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reply to donkeycorpse

I read up until about midway throuigh it, then the whole thing got too tinfoil hattish for me.
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Blackbird
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reply to La Luna

said by La Luna:

I can't even read that. My eyes man, my eyes!!!

Can anyone roll this into a nutshell in one paragraph?

How about 3 paragraphs? If it's powered and creates repetitive or pulsed waveforms, it also creates electromagnetic interference (EMI) signals capable of radiating through space and conveying information to other locations. It's a law of physics. In fact, even some unpowered stuff can radiate EMI, if it's stimulated sufficiently by other strong signals (the old ham-radio/downspout-joint problem). How strong the radiated EMI signals are, their frequencies/patterns, and whether they ever get detectably emitted outside whatever metallic enclosure that exists are all consequences of design and construction - intentionally so or not. With ordinary electronic equipment, place a sufficiently sensitive receiver close enough to the equipment case or its openings, and at some frequencies one will likely detect... something. The frequencies may move around, they may come and go, they may sound like almost anything (including pink noise)... there's an almost infinite range of possibilities.

Beyond that, whether the signals can be detected at significant distances (or what even constitutes "significant" distances), whether they carry information that can be exploited, and whether anyone actually cares are all matters for discussion, debate, and paranoia. Two generic reasons exist for concern about such signals: they can betray sensitive information riding on them to somebody who intercepts (and can figure out how to decode) them, and they can cause interference and functional perturbations in other equipment upon which they impinge. So a key design object is to keep the 'unintentional' emission levels very low on electronic equipment, both by intelligent circuit design methods and by good case-construction technology.

The military/black world often deals with extremely sensitive information that makes hostile interception methods worthwhile (as well as something to be guarded against), hence TEMPEST design criteria and testing intended to establish that any EMI is below any rational detection/exploitation levels. The rest of us may be targets of... uhmm... "varying interest" to someone bent on intercepting and decoding whatever our "stuff" emits. Whether one is of sufficient interest to "Bob" depends on a number of personal factors (YMMV); whether one is of sufficient interest to a hacker/thief depends on the cost of the interception resources he must use (breathtakingly high) and whether the payoff might ever be sufficient to justify the interception costs (it almost never would be). In reality, for most of us, any computer/display-related EMI signals are so weak and so garbled with all manner of unrelated clock, processor-bus, and random noise modulation as to render the whole mess pointless to be of concern. On the other hand, if one is a person of interest to "Bob" (or even "Ivan"), then it's within their agencies' capacities to invest in the necessary sensitive, high-powered-processing interception gear needed to make any sense of whatever (if anything) might be leaking out. The simple truth is that if or whether something like this would ever be a meaningful concern depends upon where one's own paranoia level kicks in...
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said by Blackbird:

The frequencies may move around, they may come and go, they may sound like almost anything (including pink noise)... there's an almost infinite range of possibilities.

Back in 1977 or so I had a home computer (microprocessor system) and a magazine I read had an article that showed how to program the system to "play music" by producing EMI on a nearby AM radio. Worked great Played Greensleeves.
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Name Game
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reply to Blackbird

As a young engineer spent many a days at the ITT-AOD building by you TEMPEST testing mil equipment we developed. Some went out in Space..other went on the battlefield or to FAA..rest went to the black box guys.

Calibration was always a pain in the butt..between waveguides and horns..we did the full spectrum.



Blackbird
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reply to StuartMW

said by StuartMW:

said by Blackbird:

The frequencies may move around, they may come and go, they may sound like almost anything (including pink noise)... there's an almost infinite range of possibilities.

Back in 1977 or so I had a home computer (microprocessor system) and a magazine I read had an article that showed how to program the system to "play music" by producing EMI on a nearby AM radio. Worked great

Well, back in the 70's through the early 90's, I had slightly more than "passing" involvement with some collection systems designed to exploit radiated CRT display hash. If you hooked up some of the systems' analog output signals to a speaker, some of the filtered sounds were almost musical - to such an extent that an operator could be trained to simply listen for a characteristic shift in sounds to alert him that something of interest had popped up on the target CRT screen. Decoding it reliably, however, was a whole other ballgame... it could be done, but cost dearly in terms of recording and post-processing time. I doubt much has changed with the onset of LCD displays... EMI levels are down, but processing horsepower and receiver sensitivities are up, so it's probably pretty much of a wash.
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Kearnstd
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reply to donkeycorpse

This rings of tin foil hat. And nothing more.



Blackbird
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reply to Name Game

said by Name Game:

As a young engineer spent many a days at the ITT-AOD building by you TEMPEST testing mil equipment we developed. Some went out in Space..other went on the battlefield or to FAA..rest went to the black box guys.

Calibration was always a pain in the butt..between waveguides and horns..we did the full spectrum.

Sounds like deja-vu. I always found the conducted emissions issues to be more problematic than the radiated emissions, though. Grounding design and loop-avoidance are so critical to keep signals from coupling onto external power and control lines as to be almost nightmarish... and, as you undoubtedly know, whatever conducts can just as certainly be exploited as whatever radiates.
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said by Blackbird:

I always found the conducted emissions issues to be more problematic than the radiated emissions, though.

Yup. That and ESD testing. Bastards would zap my "babies" with 8kV and look for smoke
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said by StuartMW:

said by Blackbird:

I always found the conducted emissions issues to be more problematic than the radiated emissions, though.

Yup. That and ESD testing. Bastards would zap my "babies" with 8kV and look for smoke

Then there was the day I was up on a mountain top at a nameless base running a receiver designed to operate as a reference comparison system to the one up in the aircraft conducting flight tests. Everything went fine until a desert dry storm rolled over us, and the mother-of-all-zaps hit our windowless equipment van, the antenna, and the front end of the receiver. More than a little magic smoke poured out. After we got up off the floor, the military liaison guy just looked over and said "So your box can't handle ESD, eh?"
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StuartMW
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Well to this day many an EE claims that electronics works on smoke rather than electrons. You may have heard the expression "let the smoke out" causing the component to fail (no smoke left inside to operate).

Magic Smoke

Just about every EE knows about the Smoke Test. Young and inexperienced EE's will build a whole prototype and power it up often producing clouds of smoke. Old and wiser ones power up stuff in small sections to reduce the damage.

Every EE also knows that distinctive "bang" or "pop" made by electronic components. We often walk in a lab after hearing such to watch our coworker(s) see their "babies" evaporate into smoke. Sometimes we laugh
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reply to Blackbird

said by Blackbird:

Well, back in the 70's

Back in the 60's -70's they could park outside your building and monitor you TTY.

nothing has changed

Kearnstd
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reply to Blackbird

said by Blackbird:

said by StuartMW:

said by Blackbird:

I always found the conducted emissions issues to be more problematic than the radiated emissions, though.

Yup. That and ESD testing. Bastards would zap my "babies" with 8kV and look for smoke

Then there was the day I was up on a mountain top at a nameless base running a receiver designed to operate as a reference comparison system to the one up in the aircraft conducting flight tests. Everything went fine until a desert dry storm rolled over us, and the mother-of-all-zaps hit our windowless equipment van, the antenna, and the front end of the receiver. More than a little magic smoke poured out. After we got up off the floor, the military liaison guy just looked over and said "So your box can't handle ESD, eh?"

I get the feeling he was joking.

Unless he really was not smart enough to know that nothing can be directly hardened against direct lightning strike without first employing a lightning rod as a first line of defense.
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said by Kearnstd:

I get the feeling he was joking. ...

He was. The military had a bunch of other gear up there that got fried worse than ours. Setting up a lightning suppression system was pretty much out of the question... we were reference-simulating a full airborne suite of equipment, and an aircraft isn't normally too well grounded. The meteorology guys were supposed to alert us to electrical storms coming in so we could pull the antenna cables and get our sorry butts out of there, but this one sneaked up on everyone... especially us, inside without any windows. Generally, in that setting, the biggest concern was always the van being blown off the mountain top by the gust fronts, tie-down cables notwithstanding.
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reply to donkeycorpse

Welcome to the Forum and the site. While what you posted is not what it seems, it's good to have some new blood here that is willing to post. Don't let all these curmudgeons scare you off.



StuartMW
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said by jaykaykay:

Don't let all these curmudgeons scare you off.

"a bad-tempered, difficult, cantankerous person."

Well now you'll have to say who you mean
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La Luna
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reply to jaykaykay

said by jaykaykay:

Welcome to the Forum and the site. While what you posted is not what it seems, it's good to have some new blood here that is willing to post. Don't let all these curmudgeons scare you off.

Heeeyyyyy....I resemble that remark!! LOL!