ok so let’s start with the exploits. Exploit is a bug (problem) in a piece of software that when… umm… “abused” (well the word is just exploited) it allows you to do stuff that you shouldn’t. An exploit could be live from your browser to the program you use to zip files. The top 2 reasons to use an exploit is to either get initial foothold on a machine (e.g. an exploit in a browser that would allow an attacker to execute arbitrary code when you visit their page or an exploit in winrar that when you open a zip file executes code)
From the attackers perspective, you got in, nice. Mind you you got in through means that have nothing to do with windows (and that’s true most times, especially on desktops). but now? what?
You hacked into the machine for a reason! You might wanna grab the browser cookies (giving you direct access to the accounts that the victim is logged into), grab some files, screenshots, passwords
That’s where the AV kicks in. After the initial exploit the malware behaves like a normal program. But not completely. Assuming that the AV hasn’t seen the same exact malware before (which would an insta kick ban) it’s going to see a random process accessing files in chrome’s directory. HUH. ISNT THAT SOMETHING. quarantined.
Wanna start listening to each and every keystroke? quarantined
Meanwhile the way that the exe ended up in your system was not through an installer, you don’t provide an uninstaller and it was downloaded from www.xXxveryNicEsiteyou.got. HUUUUUUUH
the whole process is a bit simplified of course, but it captures the general idea
So why does linux not have an AV? FUCK IF I KNOW! It would be very, VERY useful. Writing malware that bypasses AV is an art of its own. Can be done for sure, but it’s an extra step and it’s not fun
background: used to get paid to do shit like that (legally, pentest) and it’s a fun hobby (writing code around it, not hacking people)