Scan of front end user uploads
Craft will do some minimal cleansing of potentially malicious uploaded images by default by saving them back out to the file system and will try to sanitize SVG files as well.

It also has a relatively tame list of file extensions it allows on upload: https://docs.craftcms.com/v3/config/config-settings.html#allowedfileextensions

Anything outside of that, it'd be up to a Craft plugin or something on the server-side to do additional analysis and cleansing.