How to find it then
You can't by normal means. Maybe via a corporate firewall that has IPS/IDS or by dll monitoring.
I remember a "colleague" , showing me in real time how to evade AVs using obfuscated Mimikatz. The initial detection was originally like 15+ engines detecting it, and just by changing mimikatz attributes, it gradually went to zero detection... If I remember ESET was the last one.
Now couple it with true fileless/in-memory delivery techniques or a kernel exploit and your traditional security softs whatever awesome default-deny or AV will fail.
Why do you think corporations invest in very expensive business solutions (which are often hardware based)? And even with them, they still get breached. So I laugh when some home users products claimed to stop all malwares when basic true exploits are just enough to beat them...Yes they may stop your ordinary malware, not the complex ones like I saw.
Of course you won't see such stuff around every corner, some will say, they will never cross them (which is probably true), but we aren't in a security forum for Average Joe threats, we are here to learn how about sophisticated ones and how to protect ourselves against them.