Is it true that all circuits can act antennas?

Thread Starter

novicefedora

Joined Jun 15, 2020
12
I asked a question on StackExchange about device to measure ELF of CPU and anything to mask the ELF of CPU. I asked this after I read a report detailing how researchers used electromagnetic activity of the CPU to exfiltrate data from an airgapped system in a Faraday shield. One user who answered the question said that almost all circuits are capable of acting as antennas, if this is true, then it must mean all motherboards, CPUs, GPUs are capable of transmitting and receiving data without being connected to a WiFi or Ethernet, anyone nearby could use this phenomena to compromise the system.

Is it true that all circuits can act antennas? Can IC found on CPUs, GPUs, motherboards, etc be programmed to act as antennas to send and receive data? Is there a way to find at what frequencies they are broadcasting and receiving? What can I do to mask the ELF of CPU and higher frequencies?
 

nsaspook

Joined Aug 27, 2009
7,356
All moving charge 'creates' changing fields of some sort. Most of these fields are reactive local fields but some percentage of the fields propagate (radiation) as waves into space. The radiation percentage (you can still use local induction probes to detect this ELF energy) might be extremely tiny for lower frequencies (60Hz) and small structures or substantial for small structures inside a CPU at much higher frequencies (hundreds of MHz to GHz). Even if you air-gap and shield for EM there are other ways to detect energy from systems.

https://www.wired.com/story/monitor-ultrasonic-sounds-reveal-content-side-channel/
 

BobTPH

Joined Jun 5, 2013
2,433
Acting as an antenna Is not the same thing as transmitting data. Extracting useful data from the emissions of a cpu would be, to say the least, difficult.

Bob
 

Thread Starter

novicefedora

Joined Jun 15, 2020
12
All moving charge 'creates' changing fields of some sort. Most of these fields are reactive local fields but some percentage of the fields propagate (radiation) as waves into space. The radiation percentage (you can still use local induction probes to detect this ELF energy) might be extremely tiny for lower frequencies (60Hz) and small structures or substantial for small structures inside a CPU at much higher frequencies (hundreds of MHz to GHz). Even if you air-gap and shield for EM there are other ways to detect energy from systems.

https://www.wired.com/story/monitor-ultrasonic-sounds-reveal-content-side-channel/
So how would I block ultrasonic sounds?

Acting as an antenna Is not the same thing as transmitting data. Extracting useful data from the emissions of a cpu would be, to say the least, difficult.

Bob
What do antennas do then? Don't they transmit and receive something, which is treated as data by people utilizing it? A malware could be loaded to make the CPU broadcast data in the form of EMF, it may receive malware through that mode too.
 

Thread Starter

novicefedora

Joined Jun 15, 2020
12
Acting as an antenna Is not the same thing as transmitting data. Extracting useful data from the emissions of a cpu would be, to say the least, difficult.

Bob
I'm unable to find the link to a report I want to mention, but it said in Ivy Bride CPUs, one of it's bridges can transmit at AM radio frequency, there was a working JavaScript model of this attack in which a page allowed you to play tones and hear on certain AM radio frequency. I'm unable to find this link. You can search the net for Odini and Magneto papers which detail the attack I mentioned in the OP, if there are TEMPEST protocols to isolate the EMF, it's probably a viable hack.
 

BobTPH

Joined Jun 5, 2013
2,433
Maybe you should look up data transmission via RF and learn what it takes to transmit and receive data. A cpu will not just transmit data via RF created by its operation. It will, pretty much look like noise. For example, if the cpu was decoding an MP3 file, that does not mean you would be able to pick up and hear the sound on a radio receiver!

Bob
 

nsaspook

Joined Aug 27, 2009
7,356
Maybe you should look up data transmission via RF and learn what it takes to transmit and receive data. A cpu will not just transmit data via RF created by its operation. It will, pretty much look like noise. For example, if the cpu was decoding an MP3 file, that does not mean you would be able to pick up and hear the sound on a radio receiver!

Bob
It's pretty easy to eliminate the noise and isolate the needed signal if you have a program on the computer that generates patterns designed to isolate the needed side-channel modulation in a unique way.


These acoustic signals could obviously be RF signals with the right equipment.
 

BobTPH

Joined Jun 5, 2013
2,433
@nsaspook -- I think he is trying to block transmission, not enable it!

This reminds me of something I did during a summer intern job in 1971. My boss had a Wang programmable desktop calculator. This thing was enormous, twice the size of a typewriter, which still existed at that time. He noticed that when you wrote a loop, the Wang did the loop back by searching backwards through all the instructions for the label you were branching to. And that you could pick up an audio frequency on an FM radio, depending on how large a loop was. So I wrote a program with different sized loops for each musical note over a couple of octaves, and programmed the machine to play songs by spending the time of each note in a particular loop. Sound cards and MIDI interfaces were still far in the future...

Bob
 

MrChips

Joined Oct 2, 2009
21,349
All moving charge generate electromagnetic fields.
Can someone surreptitiously extract information from a computer by picking up RF signals? Yes but might be very difficult.
We used to put a radio on top of the cabinet of a PDP-15 minicomputer and pick up synthesized music from the computer.
 

sparky 1

Joined Nov 3, 2018
261
It is true that a computer can act as an antenna however the broader statement about all circuits can act as an antenna is an exaggeration like saying all software companies have nothing to do with virus.

It is not possible to avoid the working principles of an antenna.

There are plenty of other weak links in network security.
 
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Thread Starter

novicefedora

Joined Jun 15, 2020
12
Maybe you should look up data transmission via RF and learn what it takes to transmit and receive data. A cpu will not just transmit data via RF created by its operation. It will, pretty much look like noise. For example, if the cpu was decoding an MP3 file, that does not mean you would be able to pick up and hear the sound on a radio receiver!

Bob
@nsaspook -- I think he is trying to block transmission, not enable it!

This reminds me of something I did during a summer intern job in 1971. My boss had a Wang programmable desktop calculator. This thing was enormous, twice the size of a typewriter, which still existed at that time. He noticed that when you wrote a loop, the Wang did the loop back by searching backwards through all the instructions for the label you were branching to. And that you could pick up an audio frequency on an FM radio, depending on how large a loop was. So I wrote a program with different sized loops for each musical note over a couple of octaves, and programmed the machine to play songs by spending the time of each note in a particular loop. Sound cards and MIDI interfaces were still far in the future...

Bob
Am I the only one who sees a contradiction between your posts. A malware can be installed on the system to make it load, unload and process data which might generate usable EMF, like for example, if it has to transmit 8 bits of data, it could load and unload 8 times, as data is nothing electrical charge moving through the circuitry of the CPU, it'll propagate as EMF, which can be detected by instrument and interpreted. You should read the papers on Odini and Magneto, they describe how it works.
 

upand_at_them

Joined May 15, 2010
328
A malware can be installed on the system to make it load, unload and process data which might generate usable EMF
No, it can't. You've misunderstood what the research showed. Admittedly, this type of reporting happens often. Researchers discover some tiny effect and it's reported as "This changes everything!!!!"

This thread is tinfoil hat-wearing paranoia.
 

upand_at_them

Joined May 15, 2010
328
Just because TEMPEST is real doesn't legitimize the paranoia around "MY CPU can be spied on!"

The misunderstanding of the research that prompted this thread is very real.
 

nsaspook

Joined Aug 27, 2009
7,356
Just because TEMPEST is real doesn't legitimize the paranoia around "MY CPU can be spied on!"

The misunderstanding of the research that prompted this thread is very real.
Simple questions asked and answered. If a person believed it's possible to compromise all machines using the exact research methods that would be a misunderstanding on one technique, not of the entire technology.

It's unlikely YOUR CPU will be spied on because there's nothing interesting on it but precautions should be taken with sensitive information in hostile environments. (IE, Industrial Espionage)
 

upand_at_them

Joined May 15, 2010
328
Still the same flawed reasoning. "Some researchers showed an effect, therefore we can be justified in believing in an exaggeration of it." What is the research?! This matters! Did they manage to put a device in the same room, some distance away, and record meaningful data? (Hint: The answer is no.)

This thread is pointless and vague.
 

Thread Starter

novicefedora

Joined Jun 15, 2020
12
No, it can't. You've misunderstood what the research showed. Admittedly, this type of reporting happens often. Researchers discover some tiny effect and it's reported as "This changes everything!!!!"

This thread is tinfoil hat-wearing paranoia.
Just because TEMPEST is real doesn't legitimize the paranoia around "MY CPU can be spied on!"

The misunderstanding of the research that prompted this thread is very real.
Still the same flawed reasoning. "Some researchers showed an effect, therefore we can be justified in believing in an exaggeration of it." What is the research?! This matters! Did they manage to put a device in the same room, some distance away, and record meaningful data? (Hint: The answer is no.)

This thread is pointless and vague.
You are an unproductive member of this society, all your posts here are derisive without providing any basis for your views.

And malware can be created to load, unload and process data to make the CPU or any mircroprocessor generate usable EMF. What is wrong with paranoia? And what would you know if my concerns are legitimate or not? You are a random individual on the internet. My OP is not an exaggeration of the research, it's a valid concern.
 
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