Folder listing is an avoidable danger, which you do not want to have in your website. Malicious guys can get access to sensitive information – and you’re dead, Jim!
Simple addition of a .htaccess can be the easy fix.
to block folder view of say folder http://bar.com/foo/
$ cd foo/ $ nano .htaccess Options -Indexes
Save and close, and thats it ! Yay.
Check http://bar.com/foo/ again.
PS: You can forbid access to foo/file.ext by :
$ chmod 400 file.ext
That would make it completely un-available for public eyes!