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GulfTech Security Research September 04, 2008

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Vendor : Zen Ventures, LLC

URL : http://www.zen-cart.com

Version : Zen Cart <= 1.3.8a

Risk : SQL Injection

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Description:
Zen Cart is a full featured open source ecommerce web application
written in php that allows users to build, run and promote their
own online store. Unfortunately there are multiple SQL Injection
issues in Zen Cart that may allow an attacker to execute arbitrary
SQL queries on the underlying database. This may allow for an attacker
to gather username and password information, among other things. An
updated version of Zen Cart has been released to address these
issues and users are encouraged to upgrade as soon as possible.

SQL Injection:
There are a couple of SQL Injection issues within Zen Cart that may
allow for a malicious attacker to execute arbitrary SQL queries, and
gather arbitrary data from the database. The first issue is due to
product attribute values not being properly sanitized (particularly
the value of certain "id" parameters) when adding to or updating the
shopping cart. The queries that are vulnerable to SQL injection can
either be an update query, or an insert query depending on current
shopping cart state and whether or not the customer is logged in.
However, Zen Cart installations running with a database that supports
sub selects are vulnerable to exploitation. Otherwise the issue is
limited in regards to it's ability to be exploited.

function actionMultipleAddProduct($goto, $parameters) {
global $messageStack;
if (is_array($_POST['products_id']) && sizeof($_POST['products_id'])
> 0) {
foreach($_POST['products_id'] as $key=>$val) {
// while ( list( $key, $val ) = each($_POST['products_id']) ) {
if ($val > 0) {
$adjust_max = false;
$prodId = $key;
$qty = $val;
$add_max = zen_get_products_quantity_order_max($prodId);
$cart_qty = $this->in_cart_mixed($prodId);

The above code comes from the actionMultipleAddProduct function in
the shopping_cart class, and unlike the first issue I discussed
introduces a highly exploitable SQL Injection issue in to Zen Cart.
The root of the problem is that the in_cart_mixed function uses $prodId
in a query without any sanitation.

products_id[-99' UNION SELECT IF(SUBSTRING(admin_pass,1, 1) = CHAR(97),
BENCHMARK(1000000, MD5(CHAR(1))), null),2 FROM zencart_admin/*]

It's possible for an attacker to submit a request to the
"multiple_products_add_product" action with a products_id like the
one above (remember to set the value to one if you wish to test this)
and successfully enumerate database contents based on query response
time. Of course other attacks may be possible also depending on server
configuration. For example, if an attacker select INTO OUTFILE then
this issue can allow for remote php code execution.

Solution:
The Zen Cart developers were very prompt and professional in releasing a
fix for the previously mentioned issues. An updated version, as well as
patches can be found at the following location.

http://www.zen-cart.com/forum/showthread.php?p=604473

Credits:
James Bercegay of the GulfTech Security Research Team

Related Info:
The original advisory can be found at the following location
http://www.gulftech.org/?node=research&amp;article_id=00129-09042008