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Original release date: January 13, 2004
Last revised: April 05, 2004
Source: CERT/CC, NISCC

A complete revision history can be found at the end of this file.

Systems Affected

  • Many software and hardware systems that implement the H.323 protocol
    Examples include
    • Voice over Internet Protocol (VoIP) devices and software
    • Video conferencing equipment and software
    • Session Initiation Protocol (SIP) devices and software
    • Media Gateway Control Protocol (MGCP) devices and software
    • Other networking equipment that may process H.323 traffic (e.g., routers and firewalls)

Overview

A number of vulnerabilities have been discovered in various implementations of the multimedia telephony protocol H.323. Voice over Internet Protocol (VoIP) and video conferencing equipment and software can use these protocols to communicate over a variety of computer networks.


I. Description

The U.K. National Infrastructure Security Co-ordination Centre (NISCC) has reported multiple vulnerabilities in different vendor implementations of the multimedia telephony protocol H.323. H.323 is an international standard protocol, published by the International Telecommunications Union, used to facilitate communication among telephony and multimedia systems. Examples of such systems include VoIP, video-conferencing equipment, and network devices that manage H.323 traffic. A test suite developed by NISCC and the University of Oulu Security Programming Group (OUSPG) has exposed multiple vulnerabilities in a variety of implementations of the H.323 protocol (specifically its connection setup sub-protocol H.225.0).

Information about individual vendor H.323 implementations is available in the Vendor Information section below, and in the Vendor Information section of NISCC Vulnerability Advisory 006489/H323.

The U.K. National Infrastructure Security Co-ordination Centre is tracking these vulnerabilities as NISCC/006489/H.323. The CERT/CC is tracking this issue as VU#749342. This reference number corresponds to CVE candidate CAN-2003-0819, as referenced in Microsoft Security Bulletin MS04-001.


II. Impact

Exploitation of these vulnerabilities may result in the execution of arbitrary code or cause a denial of service, which in some cases may require a system reboot.


III. Solution

Apply a patch or upgrade

Appendix A and the Systems Affected section of Vulnerability Note VU#749342 contain information provided by vendors for this advisory. However, as vendors report new information to the CERT/CC, we will only update VU#749342. If a particular vendor is not listed, we have not received their comments. Please contact your vendor directly.

Filter network traffic

Sites are encouraged to apply network packet filters to block access to the H.323 services at network borders. This can minimize the potential of denial-of-service attacks originating from outside the perimeter. The specific services that should be filtered include

  • 1720/TCP
  • 1720/UDP
Note these are default ports only and may vary on a site-by-site basis.

If access cannot be filtered at the network perimeter, the CERT/CC recommends limiting access to only those external hosts that require H.323 for normal operation. As a general rule, filtering all types of network traffic that are not required for normal operation is recommended.

It is important to note that some firewalls process H.323 packets and may themselves be vulnerable to attack. As noted in some vendor recommendations like Cisco Security Advisory 20040113-h323 and Microsoft Security Bulletin MS04-001, certain sites may actually want to disable application layer inspection of H.323 network packets.

Protecting your infrastructure against these vulnerabilities may require careful coordination among application, computer, network, and telephony administrators. You may have to make tradeoffs between security and functionality until vulnerable products can be updated. For example, blocking port 1720/udp on segments of a network may break certain functionality related to gateway discovery..


Appendix A. - Vendor Information

This appendix contains information provided by vendors for this advisory. Please see the Systems Affected section of Vulnerability Note VU#749342 and the Vendor Information section of NISCC Vulnerability Advisory 006489/H323 for the latest information regarding the response of the vendor community to this issue.

3Com

No statement is currently available from the vendor regarding this vulnerability.

Alcatel

No statement is currently available from the vendor regarding this vulnerability.

Apple Computer Inc.

Apple: Not Vulnerable. Mac OS X and Mac OS X Server do not contain the issue described in this note.

AT&T

No statement is currently available from the vendor regarding this vulnerability.

Avaya

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Borderware

No statement is currently available from the vendor regarding this vulnerability.

Check Point

No statement is currently available from the vendor regarding this vulnerability.

BSDI

No statement is currently available from the vendor regarding this vulnerability.

Cisco Systems Inc.

Please see http://www.cisco.com/warp/public/707/cisco-sa-20040113-h323.shtml

Clavister

No statement is currently available from the vendor regarding this vulnerability.

Computer Associates

No statement is currently available from the vendor regarding this vulnerability.

Cyberguard

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Debian

No statement is currently available from the vendor regarding this vulnerability.

D-Link Systems

No statement is currently available from the vendor regarding this vulnerability.

Conectiva

No statement is currently available from the vendor regarding this vulnerability.

EMC Corporation

No statement is currently available from the vendor regarding this vulnerability.

Engarde

No statement is currently available from the vendor regarding this vulnerability.

eSoft

We don't have an H.323 implementation and thus aren't affected by this.

Extreme Networks

No statement is currently available from the vendor regarding this vulnerability.

F5 Networks

No statement is currently available from the vendor regarding this vulnerability.

Foundry Networks Inc.

No statement is currently available from the vendor regarding this vulnerability.

FreeBSD

No statement is currently available from the vendor regarding this vulnerability.

Fujitsu

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Global Technology Associates

No statement is currently available from the vendor regarding this vulnerability.

Hitachi

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Hewlett-Packard Company

Vulnerable

Please also see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Ingrian Networks

No statement is currently available from the vendor regarding this vulnerability.

Intel

No statement is currently available from the vendor regarding this vulnerability.

Intoto

No statement is currently available from the vendor regarding this vulnerability.

Juniper Networks

No statement is currently available from the vendor regarding this vulnerability.

Lachman

No statement is currently available from the vendor regarding this vulnerability.

Linksys

No statement is currently available from the vendor regarding this vulnerability.

Lotus Software

No statement is currently available from the vendor regarding this vulnerability.

Lucent Technologies

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Microsoft Corporation

Please see http://www.microsoft.com/technet/security/bulletin/MS04-001.asp

MontaVista Software

No statement is currently available from the vendor regarding this vulnerability.

MandrakeSoft

No statement is currently available from the vendor regarding this vulnerability.

Multi-Tech Systems Inc.

No statement is currently available from the vendor regarding this vulnerability.

NEC Corporation

No statement is currently available from the vendor regarding this vulnerability.

NetBSD

NetBSD does not ship any H.323 implementations as part of the Operating System.

There are a number of third-party implementations available in the pkgsrc system. As these products are found to be vulnerable, or updated, the packages will be updated accordingly. The audit-packages mechanism can be used to check for known-vulnerable package versions.

Netfilter

No statement is currently available from the vendor regarding this vulnerability.

NetScreen

No statement is currently available from the vendor regarding this vulnerability.

Network Appliance

No statement is currently available from the vendor regarding this vulnerability.

Nokia

No statement is currently available from the vendor regarding this vulnerability.

Nortel Networks

The following Nortel Networks Generally Available products and solutions are potentially affected by the vulnerabilities identified in NISCC Vulnerability Advisory 006489/H323 and CERT VU#749342:

Business Communications Manager (BCM) (all versions) is potentially affected; more information is available in Product Advisory Alert No. PAA 2003-0392-Global.

Succession 1000 IP Trunk and IP Peer Networking, and 802.11 Wireless IP Gateway are potentially affected; more information is available in Product Advisory Alert No. PAA-2003-0465-Global.

For more information please contact

North America: 1-800-4NORTEL or 1-800-466-7835
Europe, Middle East and Africa: 00800 8008 9009, or +44 (0) 870 907 9009

Contacts for other regions are available at
http://www.nortelnetworks.com/help/contact/global/

Or visit the eService portal at http://www.nortelnetworks.com/cs
under Advanced Search.

If you are a channel partner, more information can be found under http://www.nortelnetworks.com/pic
under Advanced Search.

Novell

No statement is currently available from the vendor regarding this vulnerability.

Objective Systems Inc.

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

OpenBSD

No statement is currently available from the vendor regarding this vulnerability.

Openwall GNU/*/Linux

No statement is currently available from the vendor regarding this vulnerability.

RadVision

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Red Hat Inc.

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Oracle Corporation

No statement is currently available from the vendor regarding this vulnerability.

Riverstone Networks

No statement is currently available from the vendor regarding this vulnerability.

Secure Computing Corporation

No statement is currently available from the vendor regarding this vulnerability.

SecureWorks

No statement is currently available from the vendor regarding this vulnerability.

Sequent

No statement is currently available from the vendor regarding this vulnerability.

Sony Corporation

No statement is currently available from the vendor regarding this vulnerability.

Stonesoft

No statement is currently available from the vendor regarding this vulnerability.

Sun Microsystems Inc.

Sun SNMP does not provide support for H.323, so we are not vulnerable. And so far we have not found any bundled products that are affected by this vulnerability. We are also actively investigating our unbundled products to see if they are affected. Updates will be provided to this statement as they become available.

SuSE Inc.

No statement is currently available from the vendor regarding this vulnerability.

Symantec Corporation

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Unisys

No statement is currently available from the vendor regarding this vulnerability.

TandBerg

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

Tumbleweed Communications Corp.

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

TurboLinux

No statement is currently available from the vendor regarding this vulnerability.

uniGone

Please see the NISCC Vulnerability Advisory 006489/H323 at http://www.uniras.gov.uk/vuls/2004/006489/h323.htm

WatchGuard

No statement is currently available from the vendor regarding this vulnerability.

Wirex

No statement is currently available from the vendor regarding this vulnerability.

Wind River Systems Inc.

No statement is currently available from the vendor regarding this vulnerability.

Xerox

Not Vulnerable

A response to this vulnerability is available from our Security Information site: http://www.xerox.com/security.

ZyXEL

No statement is currently available from the vendor regarding this vulnerability.


The CERT Coordination Center thanks the NISCC Vulnerability Management Team and the University of Oulu Security Programming Group (OUSPG) for coordinating the discovery and release of the technical details of this issue.


Feedback may be directed to the authors: Jeffrey S. Havrilla, Mindi J. McDowell, Shawn V. Hernan and Jason A. Rafail

Copyright 2004 Carnegie Mellon University.

Revision History

Jan 13, 2004:  Initial release
Jan 15, 2004:  Added caveat to filtering workaround
Jan 15, 2004:  Updated Xerox statement
Apr 05, 2004:  Updated HP statement

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