[Full-disclosure] Cisco CallManager 4.1 Input ValidationVulnerability
Mark-David McLaughlin (marmclau)
marmclau at cisco.com
Wed May 23 17:37:53 BST 2007
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In their advisory below, Marc and Stefan illustrate how to bypass the
application firewall used in Cisco CallManager. This means of bypass can
used to display graphics, scripts, or other information downloaded from
external web site. This technique may also be used to conduct cross-site
scripting attacks. Cisco confirms that the example the authors provided
bypasses the web application firewall and that there may be other
for bypassing the web application firewall.
Cisco has made improvements to the input validation mechanisms in
CallManager that may mitigate the risks associated with this security
vulnerability. These improvements have been incorporated into 4.2(3)sr2.
Future releases, 3.3(5)sr3, 4.1(3)sr5 and 4.3(1)sr1, will also include
improvements made to address this bug. This issue is being tracked by
following Cisco Bug ID:
* CSCsi12374 - Improvements in User Input Validation
Service releases of CallManager software are available at the following
Cisco CallManager is the software-based call-processing component of the
Cisco IP telephony solution that extends enterprise telephony features
functions to packet telephony network devices, such as IP phones, media
processing devices, voice-over-IP (VoIP) gateways, and multimedia
applications. The vulnerability described in this response exists in the
web application firewall used in CallManager. This feature is designed
prevent users from entering malicious code into the input fields used in
CallManager forms. The vulnerability exists because the web application
firewall fails to properly sanitize some potentially malicious tags.
To exploit these issues an attacker must convince an authenticated user
follow a specially crafted, malicious URL. A successful attack may
in the execution of arbitrary script code in the user's web browser.
For additional information on cross-site scripting (XSS) attacks and the
methods used to exploit such vulnerabilities, please refer to the Cisco
Applied Intelligence Response "Understanding Cross-Site Scripting (XSS)
Threat Vectors," which is available at the following link:
The Cisco PSIRT is not aware of any malicious use of the vulnerability
described in this document.
We would like to thank Marc Ruef and Stefan Friedi for bringing this
to our attention and for working with us toward coordinated disclosure
the issue. We greatly appreciate the opportunity to work with
on security vulnerabilities, and welcome the opportunity to review and
assist in product reports.
Product Security Incident Response Team (PSIRT) Cisco Systems, Inc.
- - -----Original Message-----
From: full-disclosure-bounces at lists.grok.org.uk
[mailto:full-disclosure-bounces at lists.grok.org.uk] On Behalf Of Stefan
Sent: Wednesday, May 23, 2007 10:11 AM
To: bugtraq at securityfocus.com
Cc: full-disclosure at lists.grok.org.uk; news at securiteam.com;
support at secunia.com
Subject: [Full-disclosure] Cisco CallManager 4.1 Input
Cisco CallManager 4.1 Input Validation Vulnerability
scip AG Vulnerability ID 2977 (03/13/2007)
Cisco CallManager, short CCM, is a professional voice-over-IP solution
that tracks active components, including among others phones, gateways,
conference bridges, transcoding resources and voicemail boxes.
Marc Ruef and Stefan Friedli found a web-based vulnerability that was
identified in Cisco CallManager 4.1 and may affect earlier versions as
The web interface of the application fails to properly santisize data
supplied by the search-form before displaying it back to the user.
Though several filters are in place to prevent the injection of <script>
Tags or action handlers such as "onclick" or "onmouseover", it is
possible to inject html-code including common attributes. This allows
the embedding of external references, e.g. images or flash resources.
The vulnerability also allows an attacker to use the "style"-attribute
on any tag to conduct arbitrary web-based attacks.
This vulnerability may be exploited by tricking authenticated users into
clicking a crafted link in order to conduct arbitrary web-based attacks.
Detection of web based attacks requires a specialized web proxy and/or
intrusion detection system. Patterns for detection of basic attacks are
available and easy to implement, though they may possibly fail on more
Server-side input validation should be improved to prevent the injection
of unauthorized code. Cisco has taken appropriate steps regarding this
issue, see vendor response (VII) for details.
VII. VENDOR RESPONSE
A representative of the Cisco Product Security Incident Response Team
(PSIRT) stated, that this kind of exploitation is blocked by
improvements to the web application firewall used in CallManager. The
Cisco PSIRT team has issued a formal security response available at:
scip AG - Security Consulting Information Process (german)
scip AG Vulnerability Database (german)
IX. DISCLOSURE TIMELINE
03/13/07 Identification of the vulnerabilities
03/13/07 Notification of the vendor
03/14/07 Response from Mark-David McLaughlin [marmclau at cisco.com]
of the PSIRT
03/19/07 Status Notification by PSIRT
03/28/07 Status Notification by PSIRT
04/18/07 Status Notification by PSIRT
04/20/07 Status Notification by PSIRT
05/02/07 Status Notification by PSIRT
05/05/07 Coordination of public release
05/16/07 Final Vendor Response received
05/23/07 Public Release
The vulnerabilities were discovered by Marc Ruef and Stefan Friedli.
Marc Ruef, scip AG, Zuerich, Switzerland
Stefan Friedli, scip AG, Zuerich, Switzerland
Thanks to Mark-David McLaughlin (PSIRT) for cooperating.
A2. LEGAL NOTICES
Copyright (c) 2007 scip AG, Switzerland.
Permission is granted for the re-distribution of this alert. It may not
be edited in any way without permission of scip AG.
The information in the advisory is believed to be accurate at the time
of publishing based on currently available information. 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 from use of or reliance on this advisory.
Full-Disclosure - We believe in it.
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