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My audio interface has SSH enabled by default

hhh.hn

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Re: My audio interface has SSH enabled by default

#51
post #19

I really want to know how he solved this problem, which I also face: >last year i bought a Rodecaster Duo to solve some audio woes to allow myself and my girlfriend to have microphones to our respective computers when gaming together and talking on discord in the same room without any echo

the rodecaster can connect to two computers, and we are both generally in the same discord call. so we have both microphones routed into one input for a computer, and the other person joins with their mic muted and the audio just comes from one client. since the mixing is local there's no echo. email me if you have more questions :)

So both mics will pick up both people (at least somewhat, in the same room) - but because there is no, I assume 20-100ms latency going through the system, to discord, and back - it avoids a slight difference in timing of the two mics picking up the same sound slightly differently. Is that right?

Very cool!

Re: My audio interface has SSH enabled by default

#52
post #31
post #19

Earlier quoted context omitted.

the rodecaster can connect to two computers, and we are both generally in the same discord call. so we have both microphones routed into one input for a computer, and the other person joins with their mic muted and the audio just comes from one client. since the mixing is local there's no echo. email me if you have more questions :)

Why connect it to both computers?

It saves on rewiring stuff. Maybe there's only one person talking today. Maybe they're using PC A, or perhaps they're using PC B instead.

Or maybe there's two people in the room, each on different channels altogether. In this case the other person is just uncorrelated background noise instead of a persistent echo.

Or, in-context: There's two people in the same room, both talking on the same Discord channel.

Anyway, audio routing is useful. Being able to route audio with two different PCs is a pretty neat feature of the rodecaster.

Re: My audio interface has SSH enabled by default

#53

Its still crazy to me that everyone has a pocket AI-hacker ready to inspect firmware and modify their devices now. You just put the agent on it and it gives you access in minutes. You would have to be a Hotz tier hacker if you wanted to do anything close to this only last year, or at the very least extremely patient for long hours.

there’s barely any hacking here

the guy found this through looking at the firmware but nmap -p 22 would have also found this

So like the first thing you would do to attack the device

I found an issue exactly like this on an ISP-provided router. I am nowhere near geohot but also didn’t even do as much as the guy in the article lmao

Re: My audio interface has SSH enabled by default

#54
post #44

Earlier quoted context omitted.

Ah, EU-only. That explains why I've never heard of it, among other things.

Well... if you look behind anything that plugs into a wall socket you will see that it has ( among many other things) a CE mark. Even things in the USofA have a CE mark. If your new product cannot have its CE mark for whatever reason, you will not have the approbations to sell in the USA either. What the CRA will do, is if you do not have a "CRA" compliant product, you will not have the CE mark. Which means you will…

We don't place any value on the CE mark in the States.

A lot of consumer electronics need to be FCC compliant, which involves a process of proving that the device doesn't emit too much of the wrong EMI/RFI in the wrong places.

And safety-wise, we use tend to use ETL, UL, and CSA for testing. These are third-party Nationally Recognized Testing Labs, and their own marks are used on devices they approve. But they're only really concerned about the safety of a product. In very broad strokes: If the device is proven to be unlikely-enough to burn a house down or cause electrical shock to humans, then it gets approved.

CE is a whole different thing. No government body in the USA requires or respects a CE mark on consumer goods; that mark doesn't hold any legal weight here.

Whether good or bad, CE is just not how we roll on this side of the pond.

(Of course, none of that means that laws in the EU don't affect product availability and features here. Globalization be that way sometimes.)

Re: My audio interface has SSH enabled by default

#55

Having the firmware image just be a boring old tarball + hash sounds super nice. I wish more devices were this open, and I hope Rode won't see this and decide to lock the firmware upgrades down.

I don't want my audio interface to run SSH (and have some random authorized key added), personally.

Re: My audio interface has SSH enabled by default

#56

I think "my audio interface is a 64-bit Linux computer" would've sounded far more interesting to me as a title. Perhaps a decade or two ago, the functionality of that device would've likely been implemented on a small 16-bit or 32-bit SoC running an RTOS like VxWorks. Given how many physical controls it has, turning it into a game console seems like a logical next step.

My audio interface is a Linux computer with FPGAs inside (that actually get field-programmed), with two gigabit Ethernet jacks that each talk to different parts of the machine.

But I don't think anyone here would care about that. It's not such an unusual arrangement. I guess it's kind of impressive to use it on my desk at home, but in pro audio world it's actually kind of mundane.

Maybe I'll write about it more after I get the gumption to gain a root shell on it (or brick it, whichever comes first). I think you guys might find that part more interesting. :)

Re: My audio interface has SSH enabled by default

#58

Its still crazy to me that everyone has a pocket AI-hacker ready to inspect firmware and modify their devices now. You just put the agent on it and it gives you access in minutes. You would have to be a Hotz tier hacker if you wanted to do anything close to this only last year, or at the very least extremely patient for long hours.

From the article, it sounds like he used Claude Code as an alternative to Wireshark and Google to decode USB HID traffic and find protocol documentation, respectively.

I suppose this could save a bit of time if you don't already have Wireshark installed, with a minor risk of hallucinations.

Other than this, he used Docker for some reason* to edit ~root/.ssh/authorized_keys and /etc/shadow in the firmware tarball, then wrote a quick Python script to send the relevant HID messages and copy the modified tarball to a volume mounted from a USB drive exposed by the device in response to one of the HID messages.

Maybe he used Claude to do some of this other stuff. Who knows? But the only thing in the post or the linked scripts that wasn't immediately obvious to me is why he installed the whois package in his Ubuntu container, but it turns out that, in Debian, the mkpasswd utility is installed by the whois package for historical reasons[1].

So basically, you have to be an insane hacker, or else have a basic working knowledge of Linux system administration (or at least know how to use the man(1) command; then again Google would probably suffice as an alternative) and how to write trivial programs in any language with bindings to a USB HID library.

* Presumably because he was on a Mac and didn't have a Linux box handy to generate the hashed password (which requires using glibc crypt(3) in a way that isn't compatible with macOS libc crypt(3), so nontrivial on a Mac).

Not sure why he needed password authentication in the first place, but, at the author's request, I won't shoot him.

I will, however, point out that, unless the sshd_config file on the device already set PermitRootLogin to something other than the default "prohibit-password", password authentication wouldn't have worked to log in as root, even with PasswordAuthentication set to "yes".

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=116260

Re: My audio interface has SSH enabled by default

#59

Having the firmware image just be a boring old tarball + hash sounds super nice. I wish more devices were this open, and I hope Rode won't see this and decide to lock the firmware upgrades down.

In the off chance anybody from Rode sees this: This makes me want to purchase your gear. Don't change it. It's funny this comes up now. Tomorrow I'm dragging my Zoom R20 recorder on-site to use as an overly-featured USB audio interface for a single-mic live stream. If I'd know this about Rode a week ago I'd have purchased one of these and could have left my R20 hooked-up in the home studio!

[deleted]

Re: My audio interface has SSH enabled by default

#60
Yeah, this is pretty common once a device has any real DSP in it. There's usually some stripped-down Linux on an ARM SoC underneath, and the vendor BSP just happens to ship with sshd on.

Not necessarily malice, more like nobody on the audio side really owns the rootfs.

The big question is whether it's only listening on the USB-side network, or on the actual LAN. First one is annoying. Second one would actually bother me.

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