SEC Consult Vulnerability Lab Security Advisory < 20131227-0 >
=======================================================================
              title: XPath Injection
            product: IBM Web Content Manager (WCM)
 vulnerable version: 6.x, 7.x, 8.x
      fixed version: -
             impact: high
           homepage: https://www.ibm.com/
              found: 2013-10-27
                CVE: CVE-2013-6735
                 by: A.Antukh, S.Temnikov
                     SEC Consult Vulnerability Lab
                     https://www.sec-consult.com
=======================================================================

Vendor description:
-------------------
"IBM® Web Content Manager is designed to accelerate web content development and
deployment through Internet, intranet and extranet sites. This software enables
users to create and publish content while IT retains control. Through advanced
personalization, IBM Web Content Manager delivers the right information to the
right audience when needed, providing an exceptional customer experience"

Source: https://www-03.ibm.com/software/products/en/ibmwebcontmana


Business recommendation:
------------------------
The discovered vulnerability can be exploited _without_ authentication and
therefore pose a high security risk - it allows extraction of configuration
data from the server. The impact of the XPath vulnerability isn't researched
fully. SEC Consult suspects that it is possible to extract sensitive
information that will be useful for further attacks. The recommendation of SEC
Consult is to immediately install patches provided by the vendor.


Vulnerability overview/description:
-----------------------------------
A typical URL for a host with installed WCM looks like this:
https://[HOST]:[PORT]/wps/wcm/connect/[PATH]

The "connect" servlet provided in the standard installation of IBM Web Content
Manager parses the PATH element as follows:
[PATH] = [LIBRARY]/[SITE_AREA_PATH]/[CONTENT]

Due to insufficient validation, the "LIBRARY" element suffers from an
XPath-injection vulnerability.

An unauthenticated user is able to perform blind XPath Injection attacks e.g.
get current application configuration, enumerate nodes and extract other
valuable information from vulnerable installations of Web Content Manager.


Proof of concept:
-----------------
The vulnerability is exploited due to improper validation of the LIBRARY
parameter, which is parsed by the "connect" servlet.

The most basic cases are presented below, and allow an attacker to manipulate
logic of the request. The "false" clause causes an error, the "true" clause (if
not defined explicitly) redirects an attacker to the
"/wcm/webinterface/login/login.jsp" page.

True clause: https://[HOST]:[PORT]/wps/wcm/connect/' or 'a'='a
False clause: https://[HOST]:[PORT]/wps/wcm/connect/' or 'a'='b

Knowing the difference between responses of the true and false clauses, it is
possible to manipulate requests in order to extract the information. For
example, if the following request returns TRUE, this would give an attacker
information about the "name" property.

https://[HOST]:[PORT]/wps/wcm/connect/' or (@ibmcontentwcm:name = "pznDT") or 'a'='b

In a similar way, with use of the "jcr:like" and "jcr:contains" functions one
can effectively restore the value for the "target" property.


Vulnerable / tested versions:
-----------------------------
The vulnerability is verified to exist in the 7.0 and 8.0 versions of WCM which
are the most recent versions at the moment of writing the advisory.


Vendor contact timeline:
------------------------
2013-12-04: Contacted vendor through psirt@vnet.ibm.com.
2013-12-04: Initial vendor response.
2013-12-06: Issues will be verified.
2013-12-20: Security bulletin released.
2013-12-27: SEC Consult releases coordinated security advisory.


Solution:
---------
Apply the Interim Fix PI07777
www.ibm.com/eserver/support/fixes/fixcentral/swg/quickorder?productid=WebSphere%20Portal&brandid=5&apar=PI07777


Workaround:
-----------
No workaround available.


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


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SEC Consult Vulnerability Lab

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EOF A. Antukh / @2013