BugTraq
Syhunt: Time-Based Blind NoSQL Injection Dec 19 2011 05:51PM
Felipe M. Aragon (felipe syhunt com)
Time-Based Blind NoSQL Injection - Detecting server-side JavaScript
injection vulnerabilities

In July 2011, Bryan Sullivan, a senior security researcher at Adobe
Systems, demonstrated server-side JavaScript injection vulnerabilities
in web applications using MongoDB and other NoSQL database engines. He
demonstrated how they could be used to perform Denial of Service, File
System, Remote Command Execution, and many other attacks, including the
easy extraction of the entire contents of the NoSQL database -- a blind
NoSQL injection attack (paper here at
https://media.blackhat.com/bh-us-11/Sullivan/BH_US_11_Sullivan_Server_Si
de_WP.pdf).

We not only confirmed the published data about the NoSQL injection
vulnerabilities, but also discovered that the MongoDB shell provides a
sleep() function which makes time-based detection possible of vulnerable
web applications.

It is also possible to inject a custom sleep code, a technique that may
be used to spot injection vulnerabilities in web applications using
server-side JavaScript execution. This is not restricted to MongoDB.

Below you can find two examples of NoSQL injection vulnerabilities in
PHP that could be spotted using these techniques.

Example 1: NoSQL Injection Vulnerability in PHP

The following requests would make these (or similar) vulnerable web
application sleep for 10 seconds:

vulnerable.php?msg=1';sleep(10000);var%20foo='bar

The MongoDB sleep() function works with milliseconds.

Alternative technique using a custom sleep code:

vulnerable.php?msg=1';var%20d%20=%20new%20Date();%20var%20cd%20=%20null;
%20do%20{%20cd%20=%20new%20Date();%20}%20while(cd-d%20<%2010000);var%20f
oo='bar

<?
$mongo = new Mongo();
$db = $mongo->demo;
$id = $_GET['id'];
$js = "function() {
var id = '$id';
SOME CODE...
}";
$response = $db->execute($js);
...
?>

Example 2: NoSQL Injection Vulnerability in PHP

<?
$mongo = new Mongo();
$db = $mongo->demo;
$year = $_GET['year'];
$collection = $db->demo;
$query = 'function() {var search_year = \'' .
$year . '\';' .
'return this.publicationYear == search_year || ' .
' this.filmingYear == search_year || ' .
' this.recordingYear == search_year;}';
$cursor = $collection->find(array('$where' => $query));
...
?>

Example 3: Sleep in JavaScript

var date = new Date();
var curDate = null;
do { curDate = new Date(); }
while(curDate-date < 10000); // delay time (ms)

Solution

Always validate user input used in server-side JavaScript commands.

Article by Felipe Aragon. Originally published at
http://www.syhunt.com/?n=Articles.NoSQLInjection

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Copyright © 2011 Syhunt Cyber-Security

Disclaimer:
The information in this article is provided "as is" without
warranty of any kind. Details provided are strictly for
educational and defensive purposes.

Syhunt is not liable for any damages caused by direct or
indirect use of the information provided by this article.

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