Secure WordPress by Preventing Directory Listing
For security reasons, it’s important to make sure that people cannot navigate your /plugins/ directory.
Depending on how your server is set up, your directories may be listed for all to see when visiting those URLs. You can check on your site by visiting your plugins folder:
Add a blank index.html file to this directory to secure it so that visitors see a blank page when they go there. Adding a blank index.html file to all of your folders can be time-consuming, so if you’re comfortable editing your .htaccess file, go ahead and add this one line:
# Prevents directory listing Options -Indexes
This will secure your folders sitewide.