Need for a Webserver Security Module
It is pretty difficult to secure application softwares. Common targets are Open Source software like PHPNuke. An attacker can easily find out vulnerabilities in the code.
If your application is vulnerable to SQL injection, invoking the URL above may very well delete all user data from your application.
You can use mod_rewrite to avoid this attack. it is very easy to detect the words drop and table, and then redirect the client away from the original URL. A determined attacker could simply invoke the same URL as above but use the POST method instead of GET. Since POST variables are not considered in the normal processing of most modules, the attack would go through.
To prevent the drop table SQL injection attack with mod_security, add the following to your Apache configuration:
The only parameter is a regular expression to be applied to the incoming request. This seems achievable with mod_rewrite, but the difference here is that mod_security will detect and prevent attacks performed using either GET or POST.