Although security by obscurity is not the best policy to protect your IS assets, but it is still useful to thwarts simple network scanner or newbie crackers.
Note: This tip is written for Ubuntu Linux, the steps is similar to other GNU/Linux distro, albeit with a slight variant.
Hiding Apache2 version
Edit /etc/apache2/apache2.conf
Add these lines at the end of the file:
ServerSignature Off
ServerTokens Prod
Restart Apache2
[bash]
sudo /etc/init.d/apache2 restart
[/bash]
Hiding PHP version
Edit /etc/php5/apache2/php.ini file
Find these lines, and switch it off:
expose_php = Off
display_errors = Off
Additionally you may disable certain ‘risky’ functions in php by editing the disable_functions line:
disable_functions = phpinfo, system,show_source,
Finally, you may restart Apache2 web server.
[bash]
sudo /etc/init.d/apache2 restart
[/bash]