AUSCERT External Security Bulletin Redistribution

                    ESB-2004.0095 -- ISS Security Brief
           Checkpoint VPN-1/SecureClient ISAKMP Buffer Overflow
                             05 February 2004


        AusCERT Security Bulletin Summary

Product:                Checkpoint VPN-1 Server 4.1 SP6 with OpenSSL
                        Hotfix and prior
                        Checkpoint SecuRemote/SecureClient 4.1 build 4200
                        and prior
Publisher:              ISS
Operating System:       Nokia IPSO
Impact:                 Administrator/Root Compromise
Access Required:        Remote
CVE Names:              CAN-2004-0040

Comment: ISS X-Force bulletin:


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Internet Security Systems Security Brief
February 4, 2004

Checkpoint VPN-1/SecureClient ISAKMP Buffer Overflow

ISS X-Force has discovered a flaw in the ISAKMP processing for both the
Checkpoint VPN-1 server and Checkpoint VPN clients (Securemote/
SecureClient). These products collaborate to provide VPN access to
corporate networks for remote client computers. VPN-1 is the VPN component
commonly deployed on Checkpoint Firewall-1 installations. The IKE
component of these products allows for the unidirectional or bidirectional
authentication of two remote nodes as well as the negotiation of
cryptographic capabilities and keys. A buffer overflow vulnerability
exists when attempting to handle large certificate payloads. 


A remote attacker may exploit this flaw to remotely compromise any VPN-1
server and/or client system running SecureClient/SecureClient. X-Force has
developed functional exploit code for this vulnerability and has
demonstrated successful attacks using real-world scenarios. Successful
compromise of the VPN-1 server can lead directly to complete compromise of
the entire Checkpoint Firewall-1 server.

Remote attackers can leverage this attack to successfully compromise
heavily hardened networks by modifying or tampering with the firewall
rules and configuration. Attackers will be able to run commands under the
security context of the super-user, usually "SYSTEM", or "root". Any
properly configured Firewall-1 among the affected versions with VPN
support is vulnerable to this attack by default.

In addition, affected versions of VPN-1 SecureRemote / SecureClient are
vulnerable to complete remote compromise, expanding exposure to remote
VPN clients.

Affected Versions:

Checkpoint VPN-1 Server 4.1 up to and including SP6 with OpenSSL Hotfix
Checkpoint SecuRemote/SecureClient 4.1 up to and including build 4200

For the complete ISS X-Force Security Advisory, please visit: 


About Internet Security Systems (ISS) 
Founded in 1994, Internet Security Systems (ISS) (Nasdaq: ISSX) is a 
pioneer and world leader in software and services that protect critical 
online resources from an ever-changing spectrum of threats and misuse. 
Internet Security Systems is headquartered in Atlanta, GA, with 
additional operations throughout the Americas, Asia, Australia, Europe 
and the Middle East. 

Copyright (c) 2004 Internet Security Systems, Inc. All rights reserved 

Permission is hereby granted for the electronic redistribution of this 
document. It is not to be edited or altered in any way without the 
express written consent of the Internet Security Systems X-Force. If you 
wish to reprint the whole or any part of this document in any other 
medium excluding electronic media, please email xforce@iss.net for 

Disclaimer: The information within this paper may change without notice. 
Use of this information constitutes acceptance for use in an AS IS 
condition. There are NO warranties, implied or otherwise, with regard to 
this information or its use. Any use of this information is at the 
user's risk. In no event shall the author/distributor (Internet Security 
Systems X-Force) be held liable for any damages whatsoever arising out 
of or in connection with the use or spread of this information. 
X-Force PGP Key available on MIT's PGP key server and PGP.com's key server, 
as well as at http://www.iss.net/security_center/sensitive.php 
Please send suggestions, updates, and comments to: X-Force 
xforce@iss.net of Internet Security Systems, Inc. 

Version: 2.6.2


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