Linux Web Service Permissions

Question

I am implementing my simple webservice in linux using Apache, CGI(C++) and Flat File(Data).

I kept my WWW location path in /usr/share/www/ CGI location path in /usr/lib/cgi-bin/ Data location path in /usr/share/Data/

I just wanted to access my files located in WWW and Data only through my Apache server and CGI application. Sometimes I will updated my Data Files, some times I will copy some file from Data to WWW folder using CGI application. Important that my Data Files only should by accessed by my CGI application not by any other at any cost. So I decided to give permission and ownership just like following. But It could not copy a file from Data to WWW Folder.

sudo chmod 644 -R /usr/share/Data/
sudo chown www-data /usr/share/Data/

Its not working to copy a file from Data to WWW using my CGI application. What are the permission should I provide for the above 3 locations(WWW,CGI,Data) to secure my web service.

My Apache Configuration is,

<VirtualHost *:80>
        ServerName www.mytestsite.com
        ServerAdmin webmaster@localhost
        DocumentRoot /usr/share/www/
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
        ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
        <Directory "/usr/lib/cgi-bin/">
                AllowOverride None
                Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
                Require all granted
        </Directory>

<Directory /usr/share/www/>
        Options Indexes FollowSymLinks
        AllowOverride None
        Require all granted
        </Directory>

</VirtualHost>

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