How I discovered a hidden microphone on a Chinese NanoKVM • Hacker News Board

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

#131

Post by n5NOJwkc7kRC » Mon, Dec 08, 2025, 8:30 PM UTC

ndsipa_pomu wrote: post #116

PunchyHamster wrote: post #78

Earlier quoted context omitted.

The KVM just uses a devboard that's also sold separately and just happens to have a microphone, given how cheap the mics are having one extra SKU would probably just cost them more than savings. Also I wouldn't really consider it "server room" product. Pretty much any new server has KVM, this is more "a hobbyist needing KVM for their home server"

I can't recall seeing any server that includes KVM-over-IP, but instead they have some shitty remote access controller (e.g. Dell iDRAC) that is buggy as hell and requires a subscription to even get working.

Intel AMT? Whatever AMD calls theirs?

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

#132

Post by n5NOJwkc7kRC » Mon, Dec 08, 2025, 8:32 PM UTC

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…

The Austin airport has, or used to have, such keypads in places. (Doors from the baggage carousel area through to the airside ground staff areas, for example.)

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

#133

Post by n5NOJwkc7kRC » Mon, Dec 08, 2025, 8:39 PM UTC

stragies wrote: post #103

simoncion wrote: post #100

Earlier quoted context omitted.

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 featur…

The manual, as OP said, does not offer any explanation, why the device might show up with an additional MAC/IP at the upstream switch port, and which services it might offer. OP sounds knowledgeable enough to be able to exclude the possibility, that the additional MAC/IP could be from one of the PCs, like e.g. when playing with VMs using an internal bridge in the Hypervisor. Maybe the device has a bigger "cousin" dev…

> why the device might show up with an additional MAC/IP at the upstream switch port

> the thing acts as an Ethernet bridge

A USB-C NIC has its own MAC and would thus get its own IP.

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

#134

Post by DooMMasteR » Mon, Dec 08, 2025, 8:40 PM UTC

PunchyHamster wrote: post #75

mrbluecoat wrote: post #63

> The device initially came with a default password, and SSH access was enabled using this preset password That alone ends my trust in the brand.

...you need a password to log in onto it to change it. That's hardly unique. You could say "but they could make random one that is displayed on display!", but they also sell headless version with no display at all so that's not an option

they also fixed the issue, SSH is off by default now.

BUT BE WARNED: it runs a web-server by default with no password set from the factory, you have to configure it first run to secure it....

yeah, this article is mostly a no banger, they made some dumb oversights/mistakes with the firmware but fixed them quickly and even documented the issues and concerns. The firmware if open source after all.

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

#135

Post by n5NOJwkc7kRC » Mon, Dec 08, 2025, 8:40 PM UTC

unknown_rookie wrote: post #53

Once I dissected the code of a FDA-approved medical device, Vendys Endothelix. If connected to the internet, the device would covertly send measurement data to a specific email address. The usernames and comments baked in the code suggested Chinese development. I would be curious to know what percentage of our highly sensitive data ends up overseas.

What was "covert" about it? What is "measurement data"?

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

#136

Post by MomsAVoxell » Mon, Dec 08, 2025, 11:13 PM UTC

tayiorrobinson wrote: post #3

To be fair, the microphone _is_ listed on the specsheet of the LicheeRV Nano https://wiki.sipeed.com/hardware/en/lichee/RV_Nano/1_intro.h... I assume they didn't intend to put a mic on the KVM product, but they wanted to make a KVM product, already had this SBC product, which reusing their existing stock of helped keep cost low. Should they have been more up front about it it? Sure, and it's not great that they had a…

I'm completely fine with there being a microphone in the thing. It's literally a remote eyes/hands interface, so it being an eyes/ears/hands interface is perfectly acceptable.

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

#137

Post by heavyset_go » Tue, Dec 09, 2025, 7:08 AM UTC

firesteelrain wrote: post #107

heavyset_go wrote: post #105

Earlier quoted context omitted.

Vendor BSPs are horrible, it would not surprise me if tools like that were included with it. I used one that included everything in C:\Users\ \Desktop in it.

Was it made in China?

Depends on what part of the hardware or software stack you're talking about. In general, yes there Chinese software and hardware components. This BSP looks like it was an international effort.

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

#138

Post by jlward4th » Mon, Dec 15, 2025, 3:24 PM UTC

simoncion wrote: post #100

stragies wrote: post #97

Earlier quoted context omitted.

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 featur…

I'm not an expert on this, but know enough to know the KVM doesn't need its own IP. In fact, the KVM I replaced it with provides ethernet to both my machines (at the same time) without getting its own IP.