So the other day I was thinking about app distribution and I came across this setting in the Android settings "Allow Unknown sources". I have read a few articles about it, but none seem to discuss how secure this feature exactly is.
I was wondering if disabling this option (let's say for every listed app) can prevent the automatic download and installation of malicious software from phishing links.
It doesn't prevent download. It prevents install. So you can't install an app through any means other than adb or the play store unless you enable that option.