I. BACKGROUND
Kronolith is a web-based calendar system written in PHP and utilizing the
Horde Application Framework. It is generally installed along side Horde's
IMP web mail product. More information can be obtained at the Kronolith
site at http://www.horde.org/kronolith/
II. DESCRIPTION
Remote exploitation of a design error in Horde's Kronolith could allow an
authenticated web mail user to execute arbitrary PHP code under the
security context of the running Web server.
The vulnerability specifically exists due to a design error in the way it
includes certain files. Specifically, the 'lib/FBView.php' file contains
a
function 'Kronolith_FreeBusy_View::factory' which will include local
files
that are supplied via the 'view' HTTP GET request parameter. An excerpt
from the code follows:
177 function &factory($view)
178 {
179 $driver = basename($view);
180 require_once dirname(__FILE__) . '/FBView/' . $view . '.php';
As you can see on line 179, input validation was done. However the
resulting string was not used on line 180. Instead the unfiltered
variable
coming directly from the attacker is used. By utilizing directory
traversal
specifiers and null bytes, an attacker can trivially cause files stored
on
the Web server to be parsed as PHP code.
III. ANALYSIS
Successful exploitation could allow an attacker to include an arbitrary
local file on the affected host. Due to the lack of input validation on
$GET_['view'], directory traversal specifiers could be utilized to parse
any file on the system as PHP code.
IV. DETECTION
iDefense has confirmed that versions 2.0.1 through 2.1.3 of Horde
Kronolith
are vulnerable to this issue. Other versions are also likely to be
vulnerable.
V. WORKAROUND
iDefense is unaware of any available workarounds for this vulnerability.
VI. VENDOR RESPONSE
The Horde core team has addressed this vulnerability in versions 2.0.7 and 2.1.4 of
Kronolith.
VII. CVE INFORMATION
A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.
VIII. DISCLOSURE TIMELINE
11/21/2006 Initial vendor notification
11/21/2006 Initial vendor response
11/29/2006 Coordinated public disclosure
IX. CREDIT
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright © 2006 iDefense, Inc.
Permission is granted for the redistribution of this alert electronically. It may not be edited in
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permission.
Disclaimer: The information in the advisory is believed to be accurate at the time of publishing
based on currently available information. Use of the information constitutes acceptance for use in
an AS IS condition. There are no warranties with regard to this information. Neither the author nor
the publisher accepts any liability for any direct, indirect, or consequential loss or damage
arising from use of, or reliance on, this information.
