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How I discovered a hidden microphone on a Chinese NanoKVM

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Re: How I discovered a hidden microphone on a Chinese NanoKVM

#91

Post by Ekaros »

butvacuum wrote: post #90
ghostpepper wrote: post #50

A lot of the complaints here don't make a lot of sense and read like the author has never used an embedded linux device. The previously reported bugs are more substantial - hardcoded secrets for JWT access and firmware encryption, everything running as root, etc. However, "Chinese product uses Chinese DNS servers and it's hard to change them" or "no systemd nor apt installed" are totally expected and hardly make it "…

I think you haven't gone far enough. Most of this thread is rampant ignorance and propaganda influenced bandwagoning. 1) It's from a company known for dev boards and SoCs- not consumer products. 2) The code is available on GitHub (nice!) 3) SiSpeed actively contributes to the mainline linux kernel for RISC-V in general as well as their SoCs. 4) Security in Embedded Applications is just... Bad. Amercian, Chinese, Euro…

Also what do you really expect for 30€ or 60€ price point? On relatively low volume product. It even doing what is promised is already a good start to me. And that probably tells their priorities. Start from some already working image with wide support for features. And then add the features that are needed in specific use case. And then ship it.

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#93

Post by NoMoreNicksLeft »

CamperBob2 wrote: post #89
f1shy wrote: post #30

Earlier quoted context omitted.

Do you have a pointer to learn more about the ATM keyboards? I would love to learn more about it

One really-cool way to solve that problem is to embed a 7-segment LED under each keycap. You walk up to the keypad and the 0-9 digits appear in random order. No one can shoulder-surf, look for wear or IR emission from the buttons, or train on the click sounds. Dell had those on every lab door in the building back in the early 90s. You felt like 007 every time you punched in your access code. I've never seen them anyw…

And now days I can't put in my card's pin without 10 overhead cameras aimed at the register area. All the cameras of which are network-connected, video stored persistently, and high res/fidelity enough to here the little beeps as I press the keys, and to know that I've hit the enter because the screen indicates it immediately. But then Dell cared about its own security, and the grocery store doesn't give a single shit about whether my life is ruined by identity theft.

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#94

Post by nickphx »

ghostpepper wrote: post #50

A lot of the complaints here don't make a lot of sense and read like the author has never used an embedded linux device. The previously reported bugs are more substantial - hardcoded secrets for JWT access and firmware encryption, everything running as root, etc. However, "Chinese product uses Chinese DNS servers and it's hard to change them" or "no systemd nor apt installed" are totally expected and hardly make it "…

yeah.. their list of issues speaks more to their lack of experience and understanding of linux and embedded linux devices wrapped in xenophobic nonsense...

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#95

Post by mannanj »

Aachen wrote: post #8
mannanj wrote: post #4

any speaker can be tapped into as a microphone by a motivated government.

From a hardware point of view I've also noticed that speakers work like poor microphones (and LEDs like poor solar panels / light sensors), but is there any way to actually make this work on most devices without physically changing wiring? If the circuits aren't made to take measurements (or the software can't get at the readings) but only set a voltage on the wires, there wouldn't be a way to (ab)use this. I don't k…

Any was an exaggeration and less than honest on my part, I apologize. I think the speakers in most smart devices though can because they have the circuitry as another comment mentioned to record the input in reverse via software.

I think most speakers would have that today, most modern speakers. Plain speakers that just take a voltage signal though, probably not. Though how many people use those kinds of speakers today I wonder.

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#96

Post by [deleted] »

jlward4th wrote: post #84
stragies wrote: post #17

Earlier quoted context omitted.

Why did you not just login to the device, and switched off "Broadcast to multicast", or changed the destination address? Edit: Some brands of Network-KVM use this, so that you can control the target device from another device, like e.g. an App on a tablet. That way you don't have to stand next to the target device in the noisy and cold machine room

The KVM didn't have any documentation on anything related to its network interface. I ran a port scan on it but didn't know if there was a way to log into it.

[deleted]

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#97

Post by stragies »

jlward4th wrote: post #83
CoastalCoder wrote: post #32

Earlier quoted context omitted.

Is it possible for you to name the KVM model? It sounds like a potential risk is to the public.

It is this one: https://www.amazon.com/dp/B0CP4PD3SM I did post a review there citing my security concerns. Honestly I didn't go further with the investigation because if someone really has all my data, I'm worried about retribution.

Was the network port bridged to both PCs all the time (as the description makes it sound, or did only the "active" PC get a functioning network connection? Could you tell from the FDB of the upstream device, if there were more than two MAC addresses active on the port? Did you (hopefully) open it up and make PCB pictures before chucking it?

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#98

Post by knallfrosch »

Milpotel wrote: post #5

> [...] and runs a heavily stripped-down version of Linux that lacks systemd and apt. And these are just a few of the issues. ?!

Lacking software (apt) is a security issue. Having software installed (tcpdump) is also a security issue.

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#99

Post by jlward4th »

stragies wrote: post #97
jlward4th wrote: post #83

Earlier quoted context omitted.

It is this one: https://www.amazon.com/dp/B0CP4PD3SM I did post a review there citing my security concerns. Honestly I didn't go further with the investigation because if someone really has all my data, I'm worried about retribution.

Was the network port bridged to both PCs all the time (as the description makes it sound, or did only the "active" PC get a functioning network connection? Could you tell from the FDB of the upstream device, if there were more than two MAC addresses active on the port? Did you (hopefully) open it up and make PCB pictures before chucking it?

The network was active for both machines connected to it. And it had its own IP. So 3 MAC addresses in total. I didn't ever open it up. But maybe someone will be interested in buying one and exploring more.

Re: How I discovered a hidden microphone on a Chinese NanoKVM

#100

Post by simoncion »

stragies wrote: post #97
jlward4th wrote: post #83

Earlier quoted context omitted.

It is this one: https://www.amazon.com/dp/B0CP4PD3SM I did post a review there citing my security concerns. Honestly I didn't go further with the investigation because if someone really has all my data, I'm worried about retribution.

Was the network port bridged to both PCs all the time (as the description makes it sound, or did only the "active" PC get a functioning network connection? Could you tell from the FDB of the upstream device, if there were more than two MAC addresses active on the port? Did you (hopefully) open it up and make PCB pictures before chucking it?

This picture from the list of product pictures [0] indicates that the thing acts as an Ethernet bridge. It probably exposes itself as a USB-C gigabit Ethernet device to the machine it's plugged into.

Page four of TFM [1] supports this theory.

Also, this functionality is called out in the product listing and in the manual. I'm over here laughing my ass off because OP got so frightened by this clearly-documented feature that they immediately threw the thing in the trash, rather than first investigating to see if the source of the network traffic was the machines plugged into the device.

[0] https://m.media-amazon.com/images/I/71GglDmzCYL._SL1500_.jpg> (If this direct link fails, it's the image that has the header "A Stable Gigabit Ethernet Port".

[1] https://avaccess.com/wp-content/uploads/2024/01/UM-_-iDock-C...> (This is the "DOWNLOAD USER MANUAL" link in the Downloads subsection of the More Information section of [2])

[2] https://www.avaccess.com/products/idock-c20-kvm-switch-docki...>

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