What NOT to spend time/resource developing

Danal · 27 Feb 2018, 14:27

However, I would appreciate it to have a guide or page in the new wiki (or at least some ideas) on "how" one would be able to securely connect a Duet on the Internet. Reverse-Proxy, VPN, computer with TeamViewer/VNC/etc. I know that everyones environment is different, so at least a few common pointers or keywords would be nice.

I believe the Wiki is now a true Wiki, meaning we can all edit it. I'll take a shot at this page; it will be a few days before I can start.

kraegar · 27 Feb 2018, 14:57

I'll be taking my duet equipped printer to MRRF, a printer fest. I plan to shut off the wifi so no one messes with it. It's the one time I wish the wifi was more secure (or that I had a duet ethernet).

That said, the other 363 days a year I couldn't care less about security on my duets.

DjDemonD · 27 Feb 2018, 16:17

Why not take a mini router, connect it to it and then connect to a PC. If its password protected it shouldn't be accessible to anyone else there.

tomasf · 27 Feb 2018, 17:46

Statement #2 is the one I don't fully agree with. Some printers will run on networks that aren't totally private. This isn't ideal, but it's reality. Just because someone accesses my network shouldn't mean everything on it is wide open to abuse.

Any device on a network should implement basic authentication. Even if we can't have TLS any time soon, standard session-based auth (the kind used by normal websites) would is enormously better than nothing (or rather, the flawed authentication that already exists).

kraegar · 27 Feb 2018, 18:38

@DjDemonD:

Why not take a mini router, connect it to it and then connect to a PC. If its password protected it shouldn't be accessible to anyone else there.

I did that last year. The WIFI was extremely crowded with SSIDs from people doing that same thing, and connectivity was horrible. Honestly I think ethernet is the only way to go there.

DjDemonD · 27 Feb 2018, 19:13

It's a shame that Duet3D didn't make the network system modular from the off, with swappable wifi/ethernet modules, but the the retrospectoscope is rather an accurate instrument.

dc42 · 27 Feb 2018, 20:28

@kraegar:

@DjDemonD:

Why not take a mini router, connect it to it and then connect to a PC. If its password protected it shouldn't be accessible to anyone else there.

I did that last year. The WIFI was extremely crowded with SSIDs from people doing that same thing, and connectivity was horrible. Honestly I think ethernet is the only way to go there.

Maybe run the Duet in AP mode?

kraegar · 27 Feb 2018, 20:39

@dc42:

@kraegar:

@DjDemonD:

Why not take a mini router, connect it to it and then connect to a PC. If its password protected it shouldn't be accessible to anyone else there.

I did that last year. The WIFI was extremely crowded with SSIDs from people doing that same thing, and connectivity was horrible. Honestly I think ethernet is the only way to go there.

Maybe run the Duet in AP mode?

Not a bad plan. May try it. Just enough web connectivity to upload STLs if needed is all I really need, though. For the most part I just run demo prints at MRRF.

JohnOCFII · 27 Feb 2018, 21:16

@Danal:

I want to open a somewhat sensitive subject. I have fairly strong opinions on this; nonetheless, I have an open mind and would like to hear other perspectives.

I believe that Duet Firmware developers should not spend time on developing security any further (or not much further) than it exists today.

I'm in conceptual agreement.

My only concern is it seems browser vendors are moving away from support of HTTP. I'd want to ensure the firmware keeps up enough with industry to avoid situations where people have to jump through hoops to use it.

Examples of industry discussion:

http://www.zdnet.com/article/google-tightens-noose-on-http-chrome-to-stick-not-secure-on-pages-with-search-fields/
https://blog.mozilla.org/security/2015/04/30/deprecating-non-secure-http/

John

DjDemonD · 27 Feb 2018, 23:25

@kraegar:

@dc42:

@kraegar:

@DjDemonD:

Why not take a mini router, connect it to it and then connect to a PC. If its password protected it shouldn't be accessible to anyone else there.

I did that last year. The WIFI was extremely crowded with SSIDs from people doing that same thing, and connectivity was horrible. Honestly I think ethernet is the only way to go there.

Maybe run the Duet in AP mode?

Not a bad plan. May try it. Just enough web connectivity to upload STLs if needed is all I really need, though. For the most part I just run demo prints at MRRF.

Can you upload a file to a duet over usb to be started from panel due? And leave wifi off.

Danal · 28 Feb 2018, 00:48

If you take your printer to a show, and you do NOT need WiFi, you need change nothing, assuming WiFi at your home has WPA2 and a password. The SSID/Password will not be present at the show, and the printer will connect to nothing. Absolutely secure.

If you DO need WiFi, put the Duet in "Access Point" mode with an SSID and Password that you use only for that show. That way, you can connect, but no one else can. Absolutely Secure.

No router needed, in either case. The security is at the WPA2 level, not the Duet.

Markdnd · 1 Mar 2018, 22:45

Another thing to bear in mind is that, although you can use a self signed certificate, it would only stop casual snooping and is easily spoofed. To implement SSL properly (and stop browsers and web security packages bleating) would require an official SSL certificate per printer at a cost of about £40 per year.

And for what? To stop someone who already has full access to your network sniffing the username and password that most people probably haven't set in the first place.

A simpler solution would be to implement a white-list of MAC addresses that the printer will allow to connect to it. Still not exactly rocket science to defeat, I accept, but it would stop accidental connections and block the casual experimenter at public events.

Better still, get a cheap (£15) wireless AP and put it right next to your Duet WiFi then use an Ethernet connection from your PC/Laptop to it. Effectively turns the Duet into an Ethernet model with a private network. (Surround it with a Faraday cage if you want to get even more isolation)

Danal · 3 Feb 2018, 02:43

@Markdnd:

Better still, get a cheap (£15) wireless AP and put it right next to your Duet WiFi then use an Ethernet connection from your PC/Laptop to it. Effectively turns the Duet into an Ethernet model with a private network. (Surround it with a Faraday cage if you want to get even more isolation)

Duet itself has AP mode. With WPA2. No extra router needed.

Danal · 3 Feb 2018, 02:42

@Markdnd:

A simpler solution would be to implement a white-list of MAC addresses that the printer will allow to connect to it. Still not exactly rocket science to defeat, I accept, but it would stop accidental connections and block the casual experimenter at public events.

At a public event, even if the config is untouched and the Duet is still in "client" WiFi mode, it will not connect, because there are no WPA2 APs with the correct SSID and Password of the printer owner's home network.

To be clear, the SSID can't be discovered, because clients don't broadcast it.

The WiFi client in the duet will be sending an 802.11 management packet known as a "probe request". This contains NO information about the SSID; even if an 'evil' AP responds to it, that evil AP would have to have prior knowledge of the SSID and the Password of the printer owner's home network to associate and authenticate the Duet.

Short version: Config untouched, all is still secure, no one can connect, including the printer owner.

Danal · 3 Feb 2018, 02:42

To summarize two posts:

Public event. Config untouched. Perfectly secure, as the printer client has no network to which it will connect. However, printer owner can't connect either; only paneldue usable.

Public event. Config changed to AP mode with a throwaway SSID and PWD for that event (that the owner of the printer never tells anyone). Perfectly secure. And, the printer owner can connect, if they choose to put their mobile on that network.

kraegar · 2 Mar 2018, 13:28

@Danal:

To summarize two posts:

Public event. Config untouched. Perfectly secure, as the printer client has no network to which it will connect. However, printer owner can't connect either; only paneldue usable.

Public event. Config changed to AP mode with a throwaway SSID and PWD for that event (that the owner of the printer never tells anyone). Perfectly secure. And, the printer owner can connect, if they choose to put their mobile on that network.

Good call. I don't know if AP mode was implemented last year when I took my own AP. I'll probably switch it to AP mode for MRRF, and see if I can get a connection at all. If not, SD card should be good enough.

dc42 · 2 Mar 2018, 14:46

AP mode wasn't working this time last year.

Danal · 2 Mar 2018, 15:20

@dc42:

AP mode wasn't working this time last year.

Ah, did not know that. In that case, an extra router would be the secure way to have WiFi at a show.

Resummary given the above:

Public show, no config changes. All secure. No one can use WiFi, including the printer owner.

Public show, change config SSID and PWD and also bring a WiFi router, to effectively act as an AP. Printer owner can use WiFi. As can anyone he tells the SSID/PWD. Secure from everyone who doesn't have the SSID/PWD.

tomasf · 2 Mar 2018, 15:49

@Markdnd:

Another thing to bear in mind is that, although you can use a self signed certificate, it would only stop casual snooping and is easily spoofed. To implement SSL properly (and stop browsers and web security packages bleating) would require an official SSL certificate per printer at a cost of about £40 per year.)

If you configure your browser/OS to trust your self-signed cert, you get the same kind of security as an expensive bought cert. Spoofing it with a MITM attack would trigger a security warning, just like spoofing any website cert would. So there's nothing insecure about using self-signed certs, really.