How bad it is to open qBittorrent web UI port

Question

I have small home server that runs a qBittorrent in docker container, and I was wondering how bad/risky it is if I'd forward the port for the web UI so I can access it from outside my network.

I know that it's not wise to open ports mindlessly, but since the web UI needs an username and password to actually access the interface I thought it would make it harder for someone to wreak havoc on my machine/network. Or is it still easy to access other parts of my network even if the site behind the port needs authentication?

How else could I access my web UI safer from outside of my local network? I know that setting up a VPN is a fairly safe and easy solution, but is there some other option that would make it completely seamless (i.e. not even connecting to a VPN) for the user who wants to connect from the internet? For example would setting up a nginx reverse proxy with some IP/MAC filtering, or Cloudflare (or some other security measure) increase security for an open port in a significant way, so that it's worth the effort setting it up?

Just to be clear, I'm aware that there's no perfect solution and that a skilled/dedicated person probably could breach my network anyway, but my main goal is to prevent bots, common exploits, and leaving obvious vulnerabilities in my setup while keeping think relatively simple and easy to use.

Answer 1

Or is it still easy to access other parts of my network even if the site behind the port needs authentication?

These two are not related. Only and only if qBitTorrent has vulnerabilities (and its track record in regard to them is quite good actually) it will be possible.

How else could I access my web UI safer from outside of my local network?

1. VPN
2. My preferred method: firewall the port completely and allow it to be opened only via the loopback (127.0.0.1) interface and connect to it via SSH port forwarding.
3. Forward it as is but enable HTTPS to exclude MITM attacks - this is the least secure option but the easiest and most reliable to implement - no need to connect to your VPN or open an SSH connection.
4. You could use knockd: https://github.com/jvinet/knock without any extra protections. This is relatively safe but any party between you and your server can sniff the sequence of knocks and open the port for themselves. This is security through obscurity which I'm not a huge fan of.

Just to be clear, I'm aware that there's no perfect solution and that a skilled/dedicated person probably could breach my network anyway, but my main goal is to prevent bots, common exploits, and leaving obvious vulnerabilities in my setup while keeping think relatively simple and easy to use.

You have hackers in too high of a regard. I've got multiple ports open for the entire Internet for over a decade and I've never been breached. The ports open (forwarded) on my router:

• SSH(d) - a non-default port (running on port 22 results in over several hundred login attempts daily - I don't want so much junk in my security logs)
• HTTP/HTTPS (for nginx)
• Rsync(d)
• Iperf
• RDP/MSTSC (for my Windows PCs) - again a non-default port for the same reason as sshd.

It's just a question of keeping your operating systems up to date in regard to running software. If you're diligent, you must be safe.

Answer 2

In short: how much do you trust the software? How much do you care about the computer that runs those services? How well is the rest of your network defended against that computer?

For there to be a problem, there has to be a vulnerability in the software that listens, that lets the attacker perform something. There probably is such vulnerabilities - a http server is complex, and bug free software is exceedingly rare.

Second, assume a successful attack. What does this give the attackers? Access to that one computer obviously, so what value do you place in it? How much time did it take to configure it, and what consequence will loss of data have? Is there any confidential data present?

Third, what can that computer access? Does it hold your e-mail password? Is it in your home network, so it can access further assets in your home? What is those assets worth? This can to a certain extent be mitigated by isolating the machine.

There's no exact answer to what the risk is. There's no one answer to if it's worth it, but mitigations carry a cost:

• VPN increases complexity.
• A portal in front increases complexity and potentially cost.
• IP filtering requires maintaining a whitelist and reduces usability.

I don't think anyone here can tell you what to do, except the general advise: be prepared. Think through what can happen, and have a recovery plan ready.