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I have an Acer Aspire E15 5-575. I removed its WiFi card, while kept its black and white antennas intact. I did this to avoid being discovered by long or short range wireless transmissions, wanting to perhaps sniff or inject code onto nearby laptops with wireless capabilities.

According to hakshop.com: “Commercial Bluetooth monitoring equipment starts at about $10,000”.

Hypothetically, if someone around my house or neighborhood had the capability of covertly sniffing or injecting code onto operating systems through wireless transmissions, can this person still detect my black and white antennas and potentially still inject commands onto my operating system? Would shortening the length of these antennas by cutting them off help my laptop not be discovered?

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    Your title is not quite what you want to ask, and it does not match your body questions. Of course code can be transmitted through antennas, that's their entire job. I'm also confused by your combining of WiFi and Bluetooth. You seem to lump these technologies together, when they are very different. What are "black and white antennas"? One does not detect "antennas" but rather one detects radio signals. – schroeder Sep 21 '18 at 11:54
  • I think you may have a misunderstanding of how radios work and radio frequencies at a fundamental level. No intention of being rude here, but the answer to your question resides in learning more on how radios actually work. Whether or not your computer could be detected by commercial bluetooth monitoring equipment is determined entirely by if your antennas are transmitting anything, as well as if the frequencies that the system monitors include the frequencies your antennas transmit on. – xorist Sep 21 '18 at 12:44
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It is a long way from being able to sniff wireless networks out to actively inserting code in an operating system during runtime. Yes, hypothetically this can be done, but it would rely on additional security vulnerabilities to be exploitable. That said, if a MitM is possible then websites could be hacked, and the browser might be used as entry point to the OS if it is vulnerable. You would have to break through a couple of layers - but there may be shortcuts such as broken media handling or a broken driver / DMA handling.

Detecting a laptop is much easier than to actively add code to it. CPU's, GPU's and many other electronic components on the motherboard will generate a lot of radio emissions. It was perfectly possible in the old days to listen to my MSX over a bad radio receiver - which picked up much more than the frequency it was supposed to listen at - and know precisely what it was doing. I could not hear the separate CPU instructions of course, but the bootup sequence would generate very specific sounds. I presume you can do the same with a modern laptop and better equipment. Shortening or cutting off your antenna's won't "cut" the white noise coming from it. Heck, you may be leaking key strokes through the small USB cable attached to your motherboard or by sound.

If you remove the WiFi then generally you would also remove all other wireless capacities as they are commonly present in a single chip solution. In that case you would not have to worry anymore about anybody inserting code over the air. Just switching it into airplane mode or disabling the drivers will generally do the trick as well.

There is really no end to the number of security options you can go through. In the end you could TEMPEST protect your house, although that would probably gain you even more attention. Please try and balance your security needs without going overboard.

  • One of my older laptops actually makes a humming sound that changes based on what I am doing. I found that encrypting /dev/zero and writing to /dev/null with OpenSSL makes a different sound if 128-bit AES is used, as opposed to 256-bit AES. I could also tell by the sound when I was scrolling on a web page, and even if that web page had active content. I was eventually able to distinguish Wikipedia from an old Flash site. If my own human ears could do that, just imagine what dedicated technology could do! – forest Sep 22 '18 at 2:57

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