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System Bus Radio: Transmits AM radio on computers without transmitting hardware

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Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#91

Post by digi_owl »

godelmachine wrote: post #10
braythwayt wrote: post #5

In the 1970s, I read about people doing this at MIT or some such, on real computers. Our high school had a Nova 1220 minicomputer, but we had no access to assembly for it, so all I could do was write programs in BASIC. After a bit of experimentation, I was able to produce two or three distinct tones of discordant buzzing with loops. Computer music!

I think you are referring to "Foot on the Hill" being played on that Altair 8800, which cunningly made use of the radio frequency interference/ static controlled by the timing loops by the program - created by Steve Dompier . Bill Gates was confounded and astounded, and described it as, "the best demo program I've seen for the Altair…". He could not figure out how the computer could broadcast to the radio. You can re…

I am not 100%, but i could have sworn that Woz talked about other members of the club playing around with something similar the day him and Jobs went there to show of Woz's would-be Apple 1.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#92

Post by digi_owl »

ravenstine wrote: post #83

That's pretty damned clever. In a far less sophisticated way, I was able to achieve audio transmission without any extra hardware except for a ~6 foot aux audio cable. This was back when I was maybe 14 years old and I was already building RF circuits with crystal oscillators and such. Learning that audio is sampled at specific frequencies, I was then lead to wonder if the same principles used to send and receive audi…

AM is basically and audio signal applied to a carrier wave, while FM is a whole different beast. Meaning that AM is quite similar to what pass down a speaker wire.

I am not a professional, but my impression is that AUX mode basically just pass the input audio signal directly to the speakers.

I am not quite sure what you mean by an open ended cable though, nor what end of the setup you upped the volume one (i suspect the PC).

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#93

Post by ravenstine »

digi_owl wrote: post #92
ravenstine wrote: post #83

That's pretty damned clever. In a far less sophisticated way, I was able to achieve audio transmission without any extra hardware except for a ~6 foot aux audio cable. This was back when I was maybe 14 years old and I was already building RF circuits with crystal oscillators and such. Learning that audio is sampled at specific frequencies, I was then lead to wonder if the same principles used to send and receive audi…

AM is basically and audio signal applied to a carrier wave, while FM is a whole different beast. Meaning that AM is quite similar to what pass down a speaker wire. I am not a professional, but my impression is that AUX mode basically just pass the input audio signal directly to the speakers. I am not quite sure what you mean by an open ended cable though, nor what end of the setup you upped the volume one (i suspect…

Actually, you're correct since there's no one frequency that's being modulated. It must have been AM.

By open-ended cable, I meant that there was an audio cable coming out of my sound card but connected to nothing on the other end. That's how I remember it, anyway. Actually, I think I increased the volume output in my PC was well as the volume on my receiver.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#94

Post by shabble »

c-smile wrote: post #74
xenadu02 wrote: post #67

Earlier quoted context omitted.

Do you have a link to more information about this?

We were told about this by our lecturer in university (USSR). Discipline was "data protection / security" ("Защита данных" in Russian). The device was masqueraded as a canned "Килька черноморская в томате" (Canned fish: Black Sea sprat in tomato) and was transmitting short narrow beams upstream on schedule.

maybe something more like https://en.wikipedia.org/wiki/Acoustic_cryptanalysis ?

I suppose it could be capturing EM emissions from the printers rather than acoustic, but that would make it fundamentally more like the other TEMPEST hacks as a way to exploit unintentional emissions, rather than as a sneaky covert channel where you have control over the computer equipment, but don't have access to external interfaces to offload your stolen data.

Unless I'm misunderstanding some part of your description, anyway.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#95

Post by fernly »

Live demo at the Computer History Museum, of an IBM 1401 playing music via AM radio bus emissions.

https://www.youtube.com/watch?v=EPk8MVEmiTI

You can see the 1401 demo'd on Wednesdays and Saturdays -- although they don't do this in the regular demo, just read cards and print on the line printer.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#96

Post by maxxxxx »

kabdib wrote: post #21

I debugged a boot issue on the Apple Newton this way. The latest flash image was a brick on production hardware (no available LEDs, GPIOs, etc.) but not on development hardware. But I could flash a new OS image. So I wrote some small loops that did different stuff on the bus (so that they sounded different) and salted the boot path with them, then listened in on my portable AM radio. Found the problem inside of an ho…

Logging by sound? I love it.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#97

Post by uhny-uftz »

mark-r wrote: post #6
braythwayt wrote: post #5

In the 1970s, I read about people doing this at MIT or some such, on real computers. Our high school had a Nova 1220 minicomputer, but we had no access to assembly for it, so all I could do was write programs in BASIC. After a bit of experimentation, I was able to produce two or three distinct tones of discordant buzzing with loops. Computer music!

I saw it done in the 1970s on a PDP-8 at the University of Minnesota. It wasn't just a couple of tones, it was playing complete songs. Later on a Z80 micro. Computers really emitted a lot of RF back then!

When I was a kid in the early 80's, I couldn't use my TRS-80 Model I during prime time TV hours. The main TV antenna for the house was located in the attic above my room. When I turned on my computer, the interference would essentially wipe out the VHF-Lo channels. Sometimes I would forget until I heard my parents yelling from across the house. Ah... good times...

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#99

Post by AlexVranas »

If I were to run this on a VM, would the host machine start transmitting AM, or would the hypervisor ruin the mechanism in which this works?

I rent a VPS at a nearby datacenter, and I could maybe ask for a tour. It would be interesting if I could pick up these signals from their server racks by running the code on my VM.

Re: System Bus Radio: Transmits AM radio on computers without transmitting hardware

#100

Post by AlexVranas »

kibwen wrote: post #55
dsign wrote: post #34

People had fanciful minds. They had expected the civilization to end in bio-warfare, or atomic bombs, or a blazing meteorite impact. No such luck. The end of the civilization came, rather anticlimactically, when the humans discovered that side effects and timing attacks made any form of cyber-security a joke. Their computers screeched to a halt bogged down by nightmarish security patches. By then, it was already too…

This code is more fun and interesting than scary. The only way this could be used maliciously would be in the one-in-a-million environment where arbitrary code execution is possible but exfiltration is difficult and where the attacker has physical proximity to the machine. The other 999,999 times, if you have ACE then it's much simpler to just exfiltrate via the network or USB or etc.

>where the attacker has physical proximity to the machine.

There may also be an option to use a directional antenna to pick it up from a great distance away.

Physical infiltration of networks isn't a fictional concept. It does happen all the time.

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