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Reverse Engineering Bambu Connect

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361–367 of 367 posts

Re: Reverse Engineering Bambu Connect

#361

Earlier quoted context omitted.

Ford actually does this. They have something called limp mode for when sensors detect degraded conditions. They won't honor the warranty if you clear the code manually and continue operating the vehicle. Many cars enter limp mode for when the ECU senses a possibly damaging condition. This limits the performance and capabilities until someone with a diagnostic computer can plug it in. Many times these diagnostic compu…

Well, that still wouldn't reduce your car speed by 50%. And even for that case there would be a warning on the console and a mechanic would be able to inform what is happening. On this iphone case, there was no warning at all on the device nor there was any disclosure that they would be doing this to the phones. You know this. In either case, thank you for the ECU info.

> Well, that still wouldn't reduce your car speed by 50%.

It does actually. It limits your top speed, and your engines rev range to approximately half of redline or less. Typically you end up limited to under 45. Also, accessories and other options, like A/C are disabled. The only indication that you will get is the reduced performance and the check engine/service light (sort of how you might get a 'service battery' warning and reduced performance on a phone).

Again, not defending it, but pointing out that Apple hardly invented artificially limiting performance behind opaque warnings to prevent unwanted outcomes. Cars have had limp mode since before the iPhone was invented.

Re: Reverse Engineering Bambu Connect

#362

Maybe I'm the exception here, but I slice my files and then load them to an SD card and walk them over to my printer. It's not high tech, but since you can't clear the build plate without physically being there, I don't see much of a change. If I really wanted to monitor the build I suppose I could just point a webcam at it rather than use the existing one. But since it prints flawlessly most of the time it seems unn…

> you can't clear the build plate without physically being there

BambuLabs printers may not support this but some people do it. The idea is to use the print head to knock the part out of the bed and into a bin. Probably not worth the hassle for personal use and you may need to design the part a certain way to make it possible, but it is useful for mass production.

Re: Reverse Engineering Bambu Connect

#363
post #320

Earlier quoted context omitted.

I don't know much about LineageOS but GrapheneOS supports attestation (albeit with its own keys) and it works for all the banking apps I have had the displeasure of using here in the UK including revolut. If LineageOS did support those APIs (which it can support if it wanted to, without any blessing from Google) then presumably most if not all of those should also work. Try GOS and see if it's broken there. If it wor…

Pretty sure this also requires the banks to then accept those attestation keys. Graphene pushes for them to do this, so you can't simply run whatever open OS you want on your device (like on desktop where you can also do online banking), you need to specifically use some third party service that then tells the banking software it's really okay to run on your device. I do find this to be a bit crappy, but at the same…

They don't have the traction. In my experience almost nothing (except for google pay) uses a whitelist for the keys. They just request attestation. This is presumably because there are too many android phone vendors using too many versions of different keys to reliably check for this.

Re: Reverse Engineering Bambu Connect

#364

I've been following along with a lot of this, because having picked up one of their printers about a month ago, I was immediately very nonplussed with the security. It took some work to get it running isolated on an IoT VLAN, yet still usable from my main machine. Thus, on first blush, I welcome security improvements from them, but I'm also anxious to see what they hold. I do wonder where this is going with the keys,…

- what the key is used for: signing critical operations, most notably print and gcode commands: https://git.devminer.xyz/archive/bambu-connect/src/commit/47..., list of known MQTT commands: https://github.com/Doridian/OpenBambuAPI/blob/main/mqtt.md

- what the firmware does: verify these operations, meaning it can reject MQTT messages with an invalid/missing signature from third party software

- the big flaw with that approach: by extracting the key, third party software can get full access again

- improvement to security: none (that obfuscation layer doesn't prevent anything if the printer/cloud were vulnerable)

authentication stays the same as before: https://git.devminer.xyz/archive/bambu-connect/src/commit/47...

Re: Reverse Engineering Bambu Connect

#365

I think people are making a big nothing burger out of this. Bambu is patching a security issue. Personally I don't want any device or application to send any old G-code to my printer. Like say command the printer to basically destroy itself. Could this lead to completely locking it down in the future? Yes. But they could do that anyways. I think this is a way to stop getting their pants sued off. If they really wante…

> Bambu is patching a security issue. This isn't a security fix. As a security protocol, it wouldn't pass any kind of security audit. A security fix would be something based on a per user credential, not on obscurity. > Personally I don't want any device or application to send any old G-code to my printer. Username/password over TLS would do that better than what Bambu Lab is proposing, as an extremely simplistic exa…

> Username/password over TLS would do that better than what Bambu Lab is proposing

Already works that way and isn't affected by this update: https://wiki.bambulab.com/en/security-incidents-cloud-traffi..., https://github.com/Doridian/OpenBambuAPI/blob/main/mqtt.md#l...

Re: Reverse Engineering Bambu Connect

#366
post #346
post #335

Earlier quoted context omitted.

It would be interesting to know how many people buy printers with AMS or other multi-material capability. How big of a selling point is it really?

All we've really got to go by is Twitter and Reddit, and I rarely see a photo of a Bambu printer without an AMS on top of it or to the side. With it being cheaper to buy an A1 Mini, A1, or P1 WITH an AMS than a base model Prusa MK4 it's not surprising they've been so popular. It's what makes me completely baffled how much Prusa have fumbled the Core One release. It should've had an enclosed AMS style product to go al…

I think it depends a bit on what markets we're talking about. Multi-material capability is mostly something I see hobbyists use. I rarely see it in an industrial setting.

And before people say that Prusa and Bambu printers are for the home market: sure. But I have seen consumer grade 3D printers in a lot of different industries. Prusa, Bambu lab and RatRig are the most common consumer grade printers I tend to see in industrial companies. (I don't think RatRigs are that common, but in a few companies that do mechanical design and they need larger volumes I've seen them being used)

Consumer grade FDM printers are cheap to buy, very cheap to run, reliable and produce decent quality prints. Also, they are far, far better than the FDM printers that you used to be able to get from the likes of Stratasys. For the price of one of the more upscale industrial machines you can buy a sizeable print farm of FDM printers.

When you do a lot of rough prototyping it is better to have a lot of cheap printers than just one advanced printer. Having lots of printers means more people can make more prototypes per day. And it reduces the need for buying more of the expensive printers and then have people have to wait for their turn.

This is why it would be interesting to know the sales figures for multi-material systems. I think the professional market might be less visible online, but they certainly buy a lot of printers.

Re: Reverse Engineering Bambu Connect

#367

Earlier quoted context omitted.

Ford actually does this. They have something called limp mode for when sensors detect degraded conditions. They won't honor the warranty if you clear the code manually and continue operating the vehicle. Many cars enter limp mode for when the ECU senses a possibly damaging condition. This limits the performance and capabilities until someone with a diagnostic computer can plug it in. Many times these diagnostic compu…

Well, that still wouldn't reduce your car speed by 50%. And even for that case there would be a warning on the console and a mechanic would be able to inform what is happening. On this iphone case, there was no warning at all on the device nor there was any disclosure that they would be doing this to the phones. You know this. In either case, thank you for the ECU info.

> Well, that still wouldn't reduce your car speed by 50%

It reduces your speed by much more than that. Varies depending on the model, but limp mode often won't get you go past 2nd gear.

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