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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

#71

Post by LorenPechtel »

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…

Given it's history I suspect there is nothing malicious going on here, just a Chinesium approach to building something. Security isn't documented so it's made of tissue paper.

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

#72

Post by calmworm »

inetknght wrote: post #46
motbus3 wrote: post #43

Earlier quoted context omitted.

You might be right but I think we cannot assume malice when it could be laziness. It might be that the exact same board has multiple target audiences and they just rebrand it for different purposes with different pricing. That said, the microphone is so weirdly positioned that it gets suspicious indeed.

> I think we cannot assume malice when it could be laziness Why can't it be both?

Perception of laziness with an option for later maliciousness and somewhat plausible deniability.

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

#73

Post by wkat4242 »

Whoa I have a bunch of these.

But I never trusted them in the first place so they don't have internet access anyway. They're on a separate subnet. It'll be fine.

Also where my servers are there's nothing interesting to hear except more servers and 3D printers.

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

#74

Post by 15155 »

Y_Y wrote: post #23
Workaccount2 wrote: post #12

Earlier quoted context omitted.

No, because the drive circuit for a speaker is the opposite of the circuit for a microphone. The output stage of a speaker amplifier is just that, an output . The only way to record audio from a speaker, which is totally possible, is to have also purposely built an input stage also attached to the speaker. Which at that point you might as well just use a microphone... Audio input and output are not reversible.

I don't know what you mean here, I can plug a speaker into my mic slot and use that to record, just as plugging a mic into the speaker slot gives a (crappy) speaker.

A DAC and amplifier circuit is electrically incapable of processing input (on its own.)

Physically unplugging and moving a speaker to a mic input works, sure, but very few devices can do this switching electronically.

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

#75

Post by PunchyHamster »

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

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

#76

Post by nine_k »

overfeed wrote: post #65
Y_Y wrote: post #21

Earlier quoted context omitted.

just fan noise? https://arxiv.org/abs/1606.05915 Any signal that you can modulate can be an exfiltration channel, and fan noise is no different.

> Any signal that you can modulate can be an exfiltration channel, and fan noise is no different. This KVM has HDMI input and can directly emulate USB mass storage; fan-modulation is the lowest-bandwidth (side-)channel available to the attackers.

You can exfiltrate data from a machine which is not connected to the KVM. A high-security machine may be even air-gapped most of the time, but be physically nearby.

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

#78

Post by PunchyHamster »

ndsipa_pomu wrote: post #13
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…

It doesn't strike me as that useful to have a hidden microphone in a KVM product as most of the time, they're going to be stuck in server rooms with just lots of fan noise to record. Far more of an issue would be any kind of keylogger built into the software, which is why it's best to go for devices that support open source software.

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"

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

#79

Post by itopaloglu83 »

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 "…

Hanlon's Razor at work; most of the shortfalls described in the article points to incompetence more than malice.

Though I find it strange though, because I would call this the shortcomings of a crowdfunded project, but the author took it as a malicious and planned act to take over target computers and networks.

As far as I remember, some of the botnets are formed by routers that vendors refused to patch, because they're no longer being sold and not profitable to do so.

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

#80

Post by hinkley »

parineum wrote: post #41
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…

The Chinese part makes one think the Chinese could access the microphone. Nevermind that, if they could access the device, they'd also be able to read your kvm i/o.

Microphones and LEDs have been used famously for side channel attacks and also to circumvent air gaps. From a Least Power point of view this is troubling.
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