Horde 3.3.5 - 'PHP_SELF' Cross-Site Scripting

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INTERNET SECURITY AUDITORS ALERT 2009-012

- Original release date: October 13th, 2009

- Last revised: December 16th, 2009

- Discovered by: Juan Galiana Lara

- CVE ID: CVE-2009-3701

- Severity: 6.3/10 (CVSS Base Score)

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I. VULNERABILITY

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Horde 3.3.5 "PHP_SELF" Cross-Site Scripting vulnerability



II. BACKGROUND

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The Horde Application Framework is a modular, general-purpose web

application framework written in PHP.  It provides an extensive array

of classes that are targeted at the common problems and tasks involved

in developing modern web applications.



III. DESCRIPTION

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Input passed to 'PHP_SELF' variable is not properly filtered before

being returned to the user. This can be explotied to inject arbitrary

HTML or to execute arbitrary script code in a user's browser session

in context of an affected site. In order to successfully exploit this

vulnerability the targeted user has to be logged as an administrator.



horde-3.3.5/admin/cmdshell.php:46:<form action="<?php echo

$_SERVER['PHP_SELF'] ?>" method="post">

horde-3.3.5/admin/sqlshell.php:29:<form name="sqlshell" action="<?php

echo $_SERVER['PHP_SELF'] ?>" method="post">

horde-3.3.5/admin/phpshell.php:42:<form action="<?php echo

$_SERVER['PHP_SELF'] ?>" method="post">



In order to filter the "PHP_SELF" variable, the htmlspecialchars

function has to be used, like in

'horde-3.3.5/templates/shares/edit.inc' file:



horde-3.3.5/templates/shares/edit.inc:1:<form name="edit"

method="post" action="<?php echo

htmlspecialchars($_SERVER['PHP_SELF']) ?>">



IV. PROOF OF CONCEPT

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This PoC will show an alert with the text "8"



http://site/horde-3.3.5/admin/phpshell.php/%22%3E%3Cscript%3Ealert%288%29;%3C/script%3E%3Cform%20/?Horde=<sessid>

http://site/horde-3.3.5/admin/cmdshell.php/%22%3E%3Cscript%3Ealert%288%29;%3C/script%3E%3Cform%20/?Horde=<sessid>

http://site/horde-3.3.5/admin/sqlshell.php/%22%3E%3Cscript%3Ealert%288%29;%3C/script%3E%3Cform%20/?Horde=<sessid>



V. BUSINESS IMPACT

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Is possible to execute arbitrary HTML or script code in a targeted

user's browser. Only works with administration sessions.



VI. SYSTEMS AFFECTED

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Horde 3.3.5 is vulnerable, others may be affected.



VII. SOLUTION

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Upgrade to version 3.3.6



VIII. REFERENCES

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http://www.horde.org

http://lists.horde.org/archives/announce/2009/000529.html

http://www.isecauditors.com



IX. CREDITS

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This vulnerability has been discovered by

Juan Galiana Lara (jgaliana (at) isecauditors (dot) com).



X. REVISION HISTORY

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October   13, 2009: Initial release

October   19, 2009: Added CVE id.

December  13, 2009: Revision.

December  16, 2009: Las revision.



XI. DISCLOSURE TIMELINE

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October   13, 2009: Vulnerability discovered by

                    Internet Security Auditors.

October   13, 2009: Sent to developers.

                    The issue is considered hard to exploit and

                    solution is delayed.

December  13, 2009: Second contact for correction plan.

December  15, 2009: New release published.

December  16, 2009: Sent to public lists.



XII. LEGAL NOTICES

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The information contained within this advisory is supplied "as-is"

with no warranties or guarantees of fitness of use or otherwise.

Internet Security Auditors accepts no responsibility for any damage

caused by the use or misuse of this information.