xss-plugin.php

<?php  
/* 
Plugin Name: Block Bad Queries 
Plugin URI: http://perishablepress.com/press/2009/12/22/protect-wordpress-against-malicious-url-requests/ 
Description: Protect WordPress Against Malicious URL Requests 
Author URI: http://perishablepress.com/ 
Author: Perishable Press 
Version: 1.0 
*/  
global $user_ID; if($user_ID) {  
    if(!current_user_can('level_10')) {  
        if (strlen($_SERVER['REQUEST_URI']) > 255 ||  
            strpos($_SERVER['REQUEST_URI'], "eval(") ||  
            strpos($_SERVER['REQUEST_URI'], "CONCAT") ||  
            strpos($_SERVER['REQUEST_URI'], "UNION SELECT") ||  
            strpos($_SERVER['REQUEST_URI'], "base64")) {  
                @header("HTTP/1.1 414 Request-URI Too Long");  
                @header("Status: 414 Request-URI Too Long");  
                @header("Connection: Close");  
                @exit;  
        }  
    }  
} ?>