OSEC

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Subject: BEA's WebLogic force handlers show code vulnerability
From: stuart.mcclureFOUNDSTONE.COM
Date: Fri Jul 28 2000 - 13:27:22 CDT


                            Foundstone, Inc.
                        http://www.foundstone.com
                      "Securing the Dot Com World"

                           Security Advisory

         BEA's WebLogic force handlers show code vulnerability

----------------------------------------------------------------------
FS Advisory ID: FS-072800-9-BEA

Release Date: July 28, 2000

Product: WebLogic

Vendor: BEA Systems (http://www.beasys.com)

Vendor Advisory: Contact the vendor

Type: Forced Handlers: Show code vulnerability

Severity: Low to Medium (depending on JSP/JHTML coding
                        practices & web application security)

Author: Saumil Shah (saumil.shahfoundstone.com)
                        Shreeraj Shah (shreeraj.shahfoundstone.com)

Operating Systems: All operating systems

Vulnerable versions: BEA WebLogic Enterprise 5.1.x
                        BEA WebLogic Server and Express 5.1.x
                        BEA WebLogic Server and Express 4.5.x

Foundstone Advisory: http://www.foundstone.com
----------------------------------------------------------------------

Description

        Two show code vulnerabilities exist with BEA's WebLogic 5.1.0
        allowing an attacker to view the source code of any file
        within the web document root of the web server. Depending on
        web application and directory structure attacker can access
        and view unauthorized files.

Details

        1. Viewing unparsed pages by forcibly invoking SSIServlet:
        ----------------------------------------------------------

        Server Side Includes pages are processed by the SSIServlet in
        WebLogic.

        It is registered in the weblogic.properties file as follows:

        weblogic.httpd.register.*.shtml=
                weblogic.servlet.ServerSideIncludeServlet

        It turns out that the wild card (*) registration can itself be
        used as a handler to invoke the SSIServlet via a URL.

        Thus, if the file path in the URL is prefixed with /*.shtml/,
        one can force that file to be processed by SSIServlet. If used
        against other file types such as .jsp and .jhtml, unparsed jsp
        and jhtml code can be viewed.

        2. Viewing unparsed pages by forcibly invoking FileServlet:
        -----------------------------------------------------------

        WebLogic comes pre-configured with the ConsoleHelp servlet
        being registered to invoke FileServlet, as can be seen from
        the following lines in the weblogic.properties file:

        # For Console help. Do not modify.
        weblogic.httpd.register.ConsoleHelp=
                                  weblogic.servlet.FileServlet
        weblogic.httpd.initArgs.ConsoleHelp=\
                defaultFilename=/weblogic/admin/help/NoContent.html
        weblogic.allow.execute.weblogic.servlet.ConsoleHelp=everyone

        Thus, if the file path in the URL is prefixed with
        /ConsoleHelp/, it causes WebLogic to invoke FileServlet, which
        causes pages to be displayed without being parsed or compiled.

Proof of concept

        1. Using *.shtml:

        Prefixing the path to web pages with "/*.shtml/" in the URL
        causes the file to be displayed since it is processed by
        SSIServlet. For example if the URL for a file "login.jsp" is:

        http://site.running.weblogic/login.jsp

        then accessing

        http://site.running.weblogic/*.shtml/login.jsp

        would served by SSIServlet and jsp/jhtml code can be seen
        in the web browser.

        2. Using ConsoleHelp:

        Prefixing the path to web pages with "/ConsoleHelp/" in the
        URL causes the file to be displayed without being parsed or
        compiled. For example if the URL for a file "login.jsp" is:

        http://site.running.weblogic/login.jsp

        then accessing

        http://site.running.weblogic/ConsoleHelp/login.jsp

        would cause the unparsed contents of the file to show up in
        the web browser.

Solution

        Please refer to BEA security advisory BEA00-03.00.

        From the vendor (as appears in BEA00-03.00):

        (1) Apply the "Show Code" vulnerability patch available from
        BEA Technical Support. This patch is available for:

        Version: The J-Engine in BEA WebLogic Enterprise 5.1.x
                 BEA WebLogic Server and Express 5.1.x
                 BEA WebLogic Server and Express 4.5.x

        Action: Contact BEA Technical Support at supportbea.com for
                patch.

        (2) Once the patch has been applied, review the
        weblogic.propertiesfile and ensure that the following changes
        have been made:

        weblogic.httpd.register.file=weblogic.servlet.FileServlet
        weblogic.httpd.initArgs.file=defaultFilename=index.html
        weblogic.httpd.defaultServlet=file

        should be changed to:

        weblogic.httpd.register.*.html=weblogic.servlet.FileServlet
        weblogic.httpd.initArgs.*.html=defaultFilename=index.html
        weblogic.httpd.defaultServlet=*.html

        Future Service Packs for BEA WebLogic Server and Express will
        also contain the patch to address this vulnerability.

Credits

        We would like to thank BEA Systems for their prompt and
        serious reaction to this problem.

Disclaimer

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        (C) 2000 OF FOUNDSTONE, INC. AND BELIEVED TO BE ACCURATE AT
        THE TIME OF PRINTING, BUT NO REPRESENTATION OR WARRANTY IS
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        REDISTRIBUTED PROVIDED THAT NO FEE IS ASSIGNED AND THAT THE
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