Files in open directories aren't vetted. Downloading an .exe or a script from an unencrypted "Index Of" page is a high-speed lane for malware and viruses.
If you control a web server: disable directory listings everywhere except for intentionally public file repositories. Place a dummy index.html in every folder. Audit yourself with the same dorks an attacker would use. index of xxx
: Academic and medical journals, such as the BMJ Military Health or the Journal of Financial Research , use "Volume XXX" (Volume 30) to archive a full year of research articles and author indices. Professional Use of "XXX" as a Placeholder Files in open directories aren't vetted