By default, indexes should not be configured, if someone wants this it should be something required to be enabled. Please update the apache2.conf file when apache is installed to change the configuration as noted below
<Directory />
Options FollowSymLinks
AllowOverride None
Require all denied
</Directory>
<Directory /usr/share>
AllowOverride None
Require all granted
</Directory>
<Directory /var/www/>
Options Indexes FollowSymLinks <-- Remove the Indexes option from this line when Apache is installed
AllowOverride None
Require all granted
</Directory>