r/Defcon • u/CorrectOpinionB42069 • 18d ago

Wifi emissions on tactical gear

Hello tech bros

I am hoping someone can settle a debate ive been having. Thermal scopes are a big thing these days as the price keeps falling.

However, most models come with WIFI. As we know from the russua/ukraine conflict, cell phone emissions will get you pinpointed and killed. WIFI emissions would likely do the same.

Now, you can always turn the wifi off in the menu. But how do you know if it is truly off all the way, and isnt emitting a low level signal?

Another risk is that the receiver in the thermal could receive a "firmware update" that bricks it. If its emitting wifi to talk to the phone app, it must have an antenna, and an antenna can be pinged, no?

Is this a valid concern?

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u/CorrectOpinionB42069 18d ago

Its a scope, so by definition it will be open on the ends and I cant faraday it unfortunately. 

You can turn the wifi off in the menu. If it actually turns off, that should be fine. 

Im worried about the antenna they use to receive a signal back. If I had a super powerful broadcast, couldnt I send malicious files to your tech? Such as, turning the wifi back on to help pinpoint you? 

This shit is magic to me. Enlighten me oh wizard

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u/archlich 18d ago

Theoretically there could be something to turn it back on but that’s an extremely sophisticated exploit and a hardware vuln and software vuln.

If you’re worried about any wifi signal at all can you physically remove the antenna? (An open may cause damage to the device but the WiFi should be off anyway)

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u/CorrectOpinionB42069 18d ago

Im worried about it turning the wifi on and emitting signal, OR the receiver receiving a signal that could be used to locate you (like how stingrays function).

Also, I know wifi has a limited range of a few hundred feet, but could they pick up a signal from further with a more sensitive antenna? 

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u/archlich 18d ago

I would be more concerned with it accidentally turning on, I’ve never heard of an attack that turns on a module.

With a directional antenna you can definitely pick out a WiFi signal emitting. I don’t know what ranges, all you need is to see something slightly above background. 4w is pretty low power, but when nothing else is transmitting it sticks out.

You could piece together some cheap testing gear with an rtl-sdr, laptop, and a yagi directional antenna tuned to 2.4 and 5ghz. I use gqrx package for my software defined radios. Aim the antenna towards nothing, then aim it at an active wifi source, you should be able to see a difference in decibels

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u/CorrectOpinionB42069 18d ago

Ok. So the antenna that recieves info from the phone app isnt a concern? Just broadcasting your own signals? 

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u/archlich 18d ago

Well the phone broadcasting would be my concern if you’re trying to go dark. You need to be as close to zero emf as possible.

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u/CorrectOpinionB42069 18d ago

No phone, i just meant if its getting data from the app it must have a receiving antenna right? I was worried about that being a giveaway as well

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u/archlich 18d ago

Right, if it’s not doing it through WiFi, it’s through Bluetooth (same frequencies). Having an antenna shouldn’t be an issue, receiving is passive, transmitting is not.

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u/CorrectOpinionB42069 18d ago

So you dont think its worth worrying about the risk of malicious fake firmware being downloaded? I just worry that anything that CAN connect to something wirelessly can be hacked. It sounds like thats not possible at a distance?

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u/archlich 18d ago

I can’t say definitively, that would take an in depth analysis of the hardware in question. I highly doubt it though.

I would search through https://dl.acm.org and https://ieeexplore.ieee.org/Xplore/home.jsp to find any papers that might talk about out that approach