Selfhosted

I don't understand your intention, as for tips and hints and end you post on this line:

"Ps: if you have a different opinions than I do skip this post"

That's the perfect recipe for a circle jerk.

I am not a expert in Linux, and I mostly rely on very strong passwords. I also discovered recently basic stuff like changing the default SSH port. Anyone knows of implementation of 2FA on Linux?

You're likely doing security wrong. But I'm keeping relatively quiet, as requested.

Please read up on how to set a partition noexec, use AppArmor, firewall, how to keep things patched, hardened and actual security measures if you want to protect the server. Also make sure not only fail2ban is working but every login on exposed software on that server is protected against brute force. ClamAV and similar are to protect your windows clients of your mail and storage server. They will not help with linux viruses. And you got to protect your servers against security vulnerabilities, not malware. The server won't randomly execute an executable file on its harddrive on its own. Think about how did that malware get there in the first place. And why is the file executable... Don't be offended, you can install whatever you want, including ClamAV, just make sure you did the 95% of protection first if security is your concern.

The core problem with this approach is that antivirus scanning is generally based on signature recognition of malicious binaries. Behavior-based antivirus scanning mostly doesn't work and tends to generate a lot of false positives. No freely available antivirus is going to have a signature library that is kept up to date enough to be worth the effort of running it on Linux - most vulnerabilities are going to be patched long before a free service gets around to creating a signature for malware that exploits those vulnerabilities, at which point the signature would be moot. If you want antivirus that is kept up to date on a weekly or better basis, you're going to have to pay for a professional service.

That said, there are other, simpler (and probably more effective) options for hardening your systems:

• Firewall - if your servers are dedicated to specific services and you don't plan on adding many more applications, you should be able to tighten up their firewalls to have only the ports they need open and nothing else. If network security is a priority, you should start with this.
• Application Whitelisting - prevent unrecognized applications from running. There are more options for this on Windows (including the builtin Applocker), but there are some AWL options for Linux. It's a lot easier to recognize the things that you do want to run than all of the things that you don't want to run.
• Secure OS - I assume you're using Debian because it's familiar, but it is a general-purpose OS with a broad scope. Consider switching to a more stripped-down variant like Alpine Linux (it can be installed on a Pi).

I think you’re about to find out that the “belief” that Linux doesn’t need antivirus isn’t just held by everyone in this community, it’s held by the whole Linux community. Hence there being no active projects in the space.

Heck you almost don’t need any antivirus in windows anymore. Just windows defender and half a brain when it comes to what you download.

I'm a senior Linux/Kubernetes sysadmin, so I deal with system security a lot.

I don't run ClamAV on any of my servers, and there's much more important ways to secure your server than to look for Windows viruses.

If you're not already running your servers in Docker, you should. Its extremely useful for automating deployment and updates, and also sets a baseline for isolation and security that you should follow. By running all your services in docker containers, you always know that all of your subcomponents are up to date, and you can update them much faster and easier. You also get the piece of mind knowing, that even if one container is compromised by an attacker, it's very hard for them to compromise the rest of the system.

Owasp has published a top 10 security measures that you can do once you've set up Docker.

https://github.com/OWASP/Docker-Security/blob/main/dist/owasp-docker-security.pdf

This list doesn't seem like it's been updated in the last few years, but it still holds true.

1. Don't run as root, even in containers

2. Update regularly

3. Segment your network services from each other and use a firewall.

4. Don't run unnecessary components, and make sure everything is configured with security in mind.

5. Separate services by security level by running them on different hosts

6. Store passwords and secrets in a secure way. (usually this means not hardcoding them into the docker container)

7. Set resource limits so that one container can't starve the entire host.

8. Make sure that the docker images you use are trustworthy

9. Setup containers with read-only file systems, only mounting r/w tmpfs dies in specific locations

10. Log everything to a remote server so that logs cannot be tampered with. (I recommend opentelemetry collector (contrib) and loki)

The list goes into more detail.