tcpdump is not a "hacking" tool, not in a sense implied in the article.
How I discovered a hidden microphone on a Chinese NanoKVM
111–120 of 138 posts
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#112Earlier quoted context omitted.
Yes, just modulate the fan noise on the transmitter, and apply a filter on the receiver.
Doesn't being able to modulate the fan presume you already control the target device?
It's possible to get malware onto even air-gapped machines. This is a way to then communicate across the air-gap.
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#113Mics have a pretty standard look, and are hard to miss on the board. It would be more insideous if there were cheap film caps leading into a very expensive ADC. I work with with analogue audio, and it’s very important to design around the noise of cheap caps. They are for all intents and purposes microphones and if you were clever about different caps for different frequencies and good digital processing I have no do…
Why is there a component on the board that isn't used in the product for any official purpose then? Even if you believe it was an accident and an oversight (which it could have been), you should be upset because it's something that could be pretty serious if you used in your home. Just because you might claim it's not malicious, doesn't make it not negligence.
Cuz it's simply built upon the existing LicheeRV Nano SBC, then it has the same component just as the board.
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#114To 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…
"hidden microphone in a Chinese KVM" is the correct way to describe what is going on. "Reusing existing stock" is not a valid excuse. They are currently selling this device without advertising that it contains a working microphone.
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Re: How I discovered a hidden microphone on a Chinese NanoKVM
#115Earlier quoted context omitted.
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 shi…
That's why I always cover the pin pad with my other hand (probably also holding my wallet) when putting in a pin. However, I think the more likely scenario to defend against is shoulder surfers - the pin by itself is useless until combined with the card, so physical presence is needed to lift the card from me.
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#116Earlier quoted context omitted.
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"
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.
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#117Earlier quoted context omitted.
But the point of a device like this is that you (and your keyboard) are NOT physically present.
They mean the K in KVM could trivially have a keylogger. For the computers attached to that KVM. Audio is for logging for computers not attached to the device in question. Which could be up to and including a whole server room save a couple machines.
What would you be able to get from the noise of loads of servers in a room where no-one is using a keyboard?
Re: How I discovered a hidden microphone on a Chinese NanoKVM
#118To 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.
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Re: How I discovered a hidden microphone on a Chinese NanoKVM
#119Earlier 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.
Supermicro boards have it via the IPMI Ethernet port. Doesn't require any sign up.