Linux

Is it actually dangerous to run Firefox as root?

Yes, very. This is not specific to Firefox, but anything running as root gets access to everything. Only one thing has to go wrong for the whole system to get busted.

usually logged into KDE Plasma as root.

Please don't do this! DEs are not tested to be run as root! Millions of lines of code are expected to not have access to anything they shouldn't have and as such might be built to fail quietly if accessing something they shouldn't in the first place. Same thing applies to Firefox, really.

Your frame of mind is "dangerous". If you are browsing on your servers as root, you need to not manage servers anymore. If that sounded harsh, learn about attack surface area first and then I might let you back in the server room.

You won't find discussions about running browsers as root because it's not something you should need to discuss. Also, you don't need to be browsing "shady" websites to get compromised. Get that myth out of your head.

find it more convenient to use the command line from a remote desktop instead of directly SSH-ing into the system

How is extra steps and added latency more convenient? The latency of a console via remote desktop would drive me crazy. Hell, I haven't installed any kind of desktop environment on Linux server for over 20 years. It's not needed and a waste of resources. Who needs file managers anyway?

https://www.mozilla.org/en-US/security/advisories/mfsa2023-56/

That's a link to the most recent release of Firefox and the security vulnerabilities that were fixed.

You'll notice the first one listed says, "This issue could allow an attacker to perform remote code execution and sandbox escape."

So if you visited a site that exploited that bug, it escaped the sandbox and ran whatever code it wanted to. Since you were running as root it could do anything it wants. Your device is now the property of someone else. Potentially all your data has been stolen. You probably didn't even notice.

Now. Realistically. You probably didn't get exploited. Your device may not be vulnerable to that particular bug. But new bugs are found, and fixed, and created every day. Can you be sure you weren't exploited?

Let's look at it a different way. Think of it like driving a car with no seatbelt or airbags. As long as you don't crash, you're fine. The car still works fine without seatbelts and you have more freedom to move your arms around.

Let's look at it a different way. Do you ever lock the door to your home/apartment? Heck do you even close the door? Why not leave it wide open?

At the end of the day security is about layers and the trade offs for convenience. You can run KDE as root, and you can run Firefox as root. You'll probably be fine. It's like driving without a seatbelt or leaving your front door wide open, but you can do it. If you do drive with a seatbelt and at least close your front door, you can probably run KDE and Firefox as a regular user.

I think there are many security issues with your setup. You really, really shouldn't do everything as root. That is just a time bomb waiting to blow.

An overarching principle of security is that of minimum privilege: everything (every process, every person) should have the minimum privileges it needs to do what it does, and where possible, that privilege should be explicitly granted temporarily and then dropped.

This means that any issue: a security breach or a mistake can't access or break anything except whatever the component or person who had the issue could access or break, and that that access is minimal.

Suppose that you hit a page which exploits the https://www.hkcert.org/security-bulletin/mozilla-firefox-remote-code-execution-vulnerability_20230913 vulnerability in Firefox, or one like it, allowing remote code execution. If Firefox is running as root, the remote attacker now completely controls that machine. If you have SSH keys to other servers on there, they are all compromised. Your personal data could be encrypted for ransom. Anything that server manages, such as a TV or smart home equipment, could be manipulated arbitrarily, and possibly destroyed.

The same is true for any piece of software you use, because this is a general principle. Most distributions I believe don't let you ssh in as root for that reason.

In short: don't log in to anything as root; log in as a regular user and use sudo to temporarily perform administrator actions.

P.S. your description of the situation shows you don't know the nature of vulnerabilities and security - if you're running servers then this is something you should learn more about in short order.

My goodness

I don't want to step on your workflow too much since it somehow seems to work for you but your main issue stems from the fact that you clearly don't work with your server as if it actually was a server.

You shouldn't really have a desktop interface running there in the first place (let alone as root and then using it as a regular user). You should ask yourself what it actually solves for you and be open to trying different (and more standard) solutions to what you're trying to achieve.

It'd probably consist of less clicking and using the CLI a bit more, but for stuff like file management you can still easily use mc.

If you need terminal sessions that keep scrollback and don't stop when you disconnect you should learn to use tmux or screen or something like that. But then again if you're running actual software in there then you should probably use a service (daemon) for that.

As for whether it's a security issue, yeah it most definitely is. Just like it's a security issue to run literally any networked application as root. Security isn't black and white and there are trade offs to be made but most people wouldn't consider what you're doing a reasonable tradeoff.

Yes, it is. As a user you compromise only that user as a consequence of some sandbox escape. Then there may or may not be some successful privilege elevation.

I have no clue how dangerous running Firefox as root is, but it begs the question…why would you do that?

Create a user account for managing things and create a separate user for each service and/or containers.

For managing things use tmux with ssh, if you want to manage files etc. just use ranger/lf/mc. One can also mount the file system with sshfs.

As a general best practice, you should never directly login as root on any server, and those servers should be configured to not allow remote connections as the root user. You should always log in as a non-root user and only run commands as root using sudo or similar features offered by your desktop environment. You should be wary of even having an interactive root shell open; usually I would only do so on a VM console, when first setting up a system or debugging it.

By doing this, you not only guard against other people compromising your system, but also against accidentally running commands as root that could damage your system. It’s always best to only run things with the minimum permissions they need, and then only grant them additional permissions on an as-needed basis.

I just wanted to add that you can run gui applications through ssh with x11 forwarding, options -X or -Y (untrusted/trusted but at least in Debian back in the day they behaved the same). So if you wanted a gui file manager you run it in the ssh session on the remote server, sudo if you need but NEVER logged as root, and the window will pop on your local DE instead of having to run an entire desktop on each server

Just don't do that 😁

I don't get it anyway, if you login remotely, why don't you just open firefox locally but on the remote servers? This makes not much sense.

But If you absolutely have to. .. At least be careful with your surf-targets. A search-engine and wiki would most likely be fine. Some pron-, stream- or warez-sites? Nah. Surely not.

It's about as dangerous as using IE in the old days, or Edge in administrator mode.

This is like removing a safety feature in your car. Like removing seatbelts or maybe anti-lock brakes.

Without any judgement: why are your servers running X11? Just because you dislike SSH'ing to them?

Usig anything as root is a security risk.

Using any UI application as root is a bigger risk. That's because every UI toolkit loads plugins and what not from all over the place and runs the code from those plugins (e.g. plugins installed system wide and into random places some environment variables point to). Binary plugins get executed in the context of the application running and can do change every aspect of your program. I wrote a small image plugin to debug an issue once that looked at all widgets in the UI and wrote all the contents of all text fields (even those obfuscated to show only dots in the UI) to disk whenever some image was loads. Plugins in JS or other non-native code are more limited, but UI toolkits tend to have binary plugins.

So if somebody manages to set the some env vars and gets root to run some UI application with those set (e.g. using sudo), then that attacker hit the jackpot. In fact some toolkits will not even bring up any UI when run as root to avoid this.

Running any networked UI application as root is the biggest risk. Those process untrusted data by definition with who knows what set of plugins loaded.

Ideally you run the UI as a normal user and then use sudo to run individual commands as root.

You should learn how to use ssh. Running Firefox on top of Xorg is a disaster waiting to happen.

That'd be the same as asking if leaving your house front door open is dangerous -- it depends. If an ill-intended individual sees it open however, s/he won't think twice to trash your home.

On a typical home user desktop linux setup, there's virtually no difference between your regular user and root.

Access to your data, emails, passwords, installing software (in /home), access to LAN and so on are already possible without root permissions, so there really is not a whole lot that an attacker cannot do even without root.

And then, if you use sudo or su (or whatever) to switch to root with a password, escalating to root privileges is basically trivial for an attacker. An attacker can divert your PATH to compromised binaries. They could just replace "sudo" with their own little script that steals your password.

I regularly remote into in order to manage, usually logged into KDE Plasma as root. Usually they just have several command line windows and a file manager open (I personally just find it more convenient to use the command line from a remote desktop instead of directly SSH-ing into the system)

I'm not going to judge you (too much), it's your system, but that's unnecessarily risky setup. You should never need to logon to root desktop like that, even for convenience reasons.

I hope this is done over VPN and that you have 2FA configured on the VPN endpoint? Please don't tell me it's just portforward directly to a VNC running on the servers or something similar because then you have bigger problems than just random 'oops'.

I do also remember using the browser in my main server to figure out how to set up the PiHole

To be honest, you're most probably OK - malicious ad campaigns are normally not running 24/7 globally. Chances of you randomly tumbling into a malicious drive-by exploit are quite small (normally they redirect you to install fake addons/updates etc), but of course its hard to tell because you don't remember what sites you visited. Since most of this has gone through PiHole filters, I'd say there's even smaller chance to get insta-pwned.

But have a look at browser history on the affected root accounts, the sites along with timestamps should be there. You can also examine your system logs and correlate events to your browser history, look for weird login events or anything that doesn't look like "normal usage". You can set up some network monitoring stuff (like SecurityOnion) on your routers SPAN, if you're really paranoid and try to see if there's any anomalous connections when you're not using the system. You could also consider setting up ClamAV and doing a scan.

You're probably OK and that's just paranoia.

But... having mentioned paranoia... now you'll always have that nagging lack of trust in your system that won't go away. I can't speak to how you deal with that, because it's all about your own risk appetite and threat model.

Since these are home systems the potential monetary damage from downtime and re-install isn't huge, so personally I'd just take the hit and wipe/reinstall. I'd learn from my mistakes and build it all up again with better routines and hygiene. But that's what I'd do. You might choose to do something else and that might be OK too.

You seriously need to stop what you're doing. Log in with ssh only. If you need multiple terminals use multiple ssh sessions, or screen/tmux. If you need to search something do it on your desktop system.

The server should not have Firefox installed, or KDE, or anything related to desktop apps. There's no point and nothing good can come of it.

Yes. Running anything as root is potentially dangerous. And a browser is a complex and big piece of software with many security issues that can be (potentially) triggered remotely. So it's bad because of two reasons.

Btw a desktop environment also is a complex and big piece of software with potential issues. Running the whole desktop as root is another thing you wouldn't do for extra security.

The proper way is to just create a user account and run the desktop and browser as a user. Open a terminal and 'su' or 'sudo' to limit root rights to the operations that actually need those permissions.

Just running everything as root certainly works. But you do away with all the extra layers of security and end up with something as secure as MS-DOS or a Windows in the 90s or early 2000s.

No if you leave it running and don’t use it.