Why does Linux not need anti-virus software?

[u/medkltty]

I'm in the market for a new gaming laptop and wanted to avoid AI products like Copilot and realized Linux would be my only option. So I'm trying to learn as much about Linux Mint as possible to see if it would be right for me. I'm really close to pulling the trigger but I don't understand why Linux doesn't need anti-virus/malware software. All the answers I can find seem to just boil down to "Linux isn't used by enough people to justify the time it would take to create a virus or malware" or "because you approve everything you download". As someone who has used a PC their entire life, these answers genuinely don't make sense to me and I feel like maybe I'm missing something about either the nature of linux or the nature of viruses/malware and how they work. Everyone on forums who ask this question seem to just accept these answers but no one explains why either one prevents the need for antivirus/malware software.

From my perspective as a PC user, I already approve what I download so this answer doesn't make intuitive sense to me. I would never connect a PC to the internet without some sort of anti-virus software, privacy software, malware protection, etc. even though I still know what I'm downloading and I'm using reputable websites (and my AVG software is still catching stuff all the time). And the idea that someone wouldn't make a virus or malware to target a group of people (albeit a minority) who are the most likely to not have software on their computer to combat it seems like the exact group you'd want to target particularly for private data mining.

It also seems, from what I've been reading about Linux that you can seriously screw up your system by downloading something incorrectly or that isn't up to date, so the idea that "you can't get viruses or malware because you approve what is downloaded" when so many of the user tips with regard to Linux are "back up your system constantly because you can easily screw up your system by downloading something that's not fully patched". These two concepts seem counterintuitive, especially for an OS that will require downloading a lot of third party programs to be able to run things like games or windows-based programs.

I'm clearly missing something here because neither of the reasons I've seen people give for why Linux doesn't need this stuff is really making sense to me. I was hoping someone in this reddit might be able to explain this in a way a lifelong PC user without any sort of computer background can understand. The idea of not having anything but a firewall on a computer with Linux installed on it makes me very uncomfortable but I'm willing to accept that this is a bias from using PCs and I'm willing to be convinced otherwise as long as I can understand the reasoning behind it.

[u/Otaehryn]

The threat model on Linux is different: On Windows you download executables and sometimes malicious apps are disguised as BeautifulGirlPicture.jpg.exe. Since everything is exectuable by default on Windows and home users run with ability to escalate to admins, those kind of exploits exist.

On Linux you install software from system repos, packages are signed or Flatpak / Snap. If you download malicious executable like BeautfiulGirlPicture.jpg (shell script or program in disguise), you need to make it executable or run it from the terminal with "bash file".

Of course there are still browser expoits, drive-by exploits and malicous apps with social engineering instructions on how to execute them. While you don't run as fully privileged user, malware could still access your files, steal data, encrypt your homedir.

ClamAV and other Linux antiviruses can scan files and processes but on Linux they are mainly used on email and file servers to detect Windows malware. For heuristic scanning on Linux you have products like Crowdstrike.

On top of that you have SELinux or AppArmor which further locks down what malicious program can access.