A second layer of protection can be added where scripts are generally not intended to be accessed by any user. One way to do that is to block those scripts using mod_rewrite in the .htaccess file. Note: to ensure the code below is not overwritten by WordPress, place it outside the # BEGIN WordPress and # END WordPress tags in the .htaccess file. WordPress can overwrite anything between these tags.
# Block the include-only files.
RewriteRule ^wp-admin/includes/ – [F,L]
RewriteRule !^wp-includes/ – [S=3]
RewriteRule ^wp-includes/[^/]+.php$ – [F,L]
RewriteRule ^wp-includes/js/tinymce/langs/.+.php – [F,L]
RewriteRule ^wp-includes/theme-compat/ – [F,L]
# BEGIN WordPress
Note that this won’t work well on Multisite, as RewriteRule ^wp-includes/[^/]+.php$ – [F,L] would prevent the ms-files.php file from generating images. Omitting that line will allow the code to work, but offers less security.