Some times we need to hide apache banner information, because hackers check version details, before attacking a sever, If you close this door, it is more difficult for them to exploit any system holes and thus making vulnerability scanners work harder and in some cases impossible without knowing version information.
Do the following steps
Change the ServerSignature on to ServerSignature Off
Change the ServerTokens full to: ServerTokens Prod
Restart Apache: /etc/init.d/apache2 restart