"We actually looked at a browser-only implementation first."

That leads me to have two questions:

1. Could you do a browser implementation that doesn't send things to you which connects to a proxy on their client or server machine? As in, something they control handled whatever data your machines are handling.

2. If not or as a supplement, could you do paid, shared-source app they could host in arbitrary machine or VM? As in, they could inspect the product, build it from source, and deploy it to trusted hosts. They pay your company mainly for the convenience and updates.

For 1, we're going to look into it (or something like it). It sounds like the service could be improved a lot if we could implement end-to-end encryption without the MitM dangers.

For 2, those kinds of products already exist, and we're not intending to compete with them (consider Apache Guacamole, linked by another commenter somewhere in the thread).

The point about the system I described is that you wouldn't be seeing any plaintext.

It's a mistake that the ssh client requires node, I didn't know that. There's no fundamental reason you couldn't implement an in-browser ssh client the way I described, it's just more work than doing it the way you've done it.

The fact that the person responding for the site does not understand this instantly (or is able to confer with someone who does before responding) makes it very apparent that there is not nearly enough understanding of ssh to be running any type of service like this.

> in-browser Javascript can't do SSH, presumably because it lacks the right security code.

This makes it sound like you don't exactly have any idea what you're doing, which is worrying for a provider of an ssh client.

Javascript is turing complete so there is no reason in-browser javascript couldn't fully implement the ssh protocol, you "just" might have to write or port the appropriate crypto routines to javascript. And of course, you'd need a http/websocket based tcp proxy since you won't be able to do a raw tcp connection to port 22 in a browser.

(Although I'd be extremely wary of using any non-standard ssh client / crypto library implementation - who knows what timing attacks and side channel info leaks might lurk in a less-vetted implementation than openssh)

>is there something about this stack that would let us stop being a middleman?

Yes if you terminate the connection in the browser and your server just acts as a TCP<->websocket proxy, you can verify the fingerprint and (assuming you trust the JS) be sure the proxy isn't MITMing.

> It looks to me like the node SSH service would still have to be running somewhere

No.

Oh, so by "terminate the connection in the browser", you mean the service would connect via SSH to a server, start a separate socket server connected to a terminal, and then hand off the connection entirely to the browser? If not, could you explain what you mean?

If so, I can see some potential issues, but that's a really nice idea for how this could be improved, and I'll look into it more. Thanks (to you and jstanley both)!

I'm not sure I understand what you mean, but the idea is just that the shellvault server is just a dumb pipe. The only thing it does is translate from tcp to websocket and back. You you have some kind of ssh.js that does everything an ssh client does. The only problem is that the browser can't use direct TCP sockets. So instead of SSHing directly into the server you use a websocket to connect to shellvault, and shellvault forwards the data on a TCP socket to the ssh server. And of course takes the data from the TCP sockets and sends it back to the browser via websocket.

That way shellvault acts as a dumb proxy and only forwards encrypted data packets while all the crypto stuff happens in the browser and the ssh server.

Ahh, now I understand. That's worth looking into, thanks!

Not only is it completely possible, pretty sure it's already been done.... https://github.com/stuicey/SSHy

Unfortunately, that project doesn’t yet support key-based auth.

secure password auth trumps "give full access to stranger" auth any day of the week....

Agreed. But since we’re rewriting the implementation in this comment thread there should be an emphasis on E2E encrypted connections WITH key based auth. SSHy packaged up nicely with a web socket proxy through Shellvault, or any provider for that matter, would be more secure than Shellvault’s current implementation but I think the lack of being able to use key based auth would be a nonstarter for many.