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TUCoPS :: Cisco :: n-093.txt

Cisco VPN 3000 Concentrator Vulnerabilities (CIAC N-093)




             __________________________________________________________

                       The U.S. Department of Energy
                   Computer Incident Advisory Capability
                           ___  __ __    _     ___
                          /       |     /_\   /
                          \___  __|__  /   \  \___
             __________________________________________________________

                             INFORMATION BULLETIN

                  Cisco VPN 3000 Concentrator Vulnerabilities
                           [Cisco Security Advisory]

May 8, 2003 16:00 GMT                                             Number N-093
______________________________________________________________________________
PROBLEM:       Multiple vulnerabilities have been indentified for the Cisco 
               VPN 3000 series concentrators and Cisco VPN 3002 Hardware 
               Client. The Cisco VPN concentrators are a family of 
               purpose-built, remote access Virtual Private Network (VPN) 
               platforms for data encryption and authentication. 
PLATFORM:      Cisco VPN 3000 series concentrators, specifically models 3005, 
                  3015, 3030, 3060, 3080. 
               Cisco VPN 3002 Hardware Client. 
DAMAGE:        Impact ranges from performance degradation, denial of service, 
               to unintended access to private network over TCP configured 
               ports. 
SOLUTION:      Upgrade to versions 4.0.1 and 3.6.7F.
______________________________________________________________________________
VULNERABILITY  The risk is MEDIUM. A flood of malformed ICMP packets could 
ASSESSMENT:    result in performance degradation. Under certain configurations,
               an attacker could telnet to a server from a workstation on a 
			   public network. 
______________________________________________________________________________
LINKS: 
 CIAC BULLETIN:      http://www.ciac.org/ciac/bulletins/n-093.shtml 
 ORIGINAL BULLETIN:  http://www.cisco.com/warp/public/707/cisco-sa-20030507-
                        vpn3k.shtml 
______________________________________________________________________________

[***** Start Cisco Security Advisory *****]

Cisco Security Advisory: Cisco VPN 3000 Concentrator Vulnerabilities
Revision 1.2
Last Updated 2003 May 08 at 0519 UTC (GMT)
For Public Release 2003 May 07 at 1600 UTC (GMT)

------------------------------------------------------------------------------

Contents
Summary 
Affected Products 
Details 
Impact 
Software Versions and Fixes 
Obtaining Fixed Software 
Workarounds 
Exploitation and Public Announcements 
Status of This Notice: FINAL 
Distribution 
Revision History 
Cisco Security Procedures 

--------------------------------------------------------------------------------

Summary 
This advisory documents vulnerabilities for the Cisco VPN 3000 series 
concentrators and Cisco VPN 3002 Hardware Client. These vulnerabilities are 
documented as Cisco bug ID CSCea77143 (IPSec over TCP), CSCdz15393 (SSH), 
and CSCdt84906 (ICMP). There are workarounds available to mitigate the 
effects of these vulnerabilities. Upgrading to the latest version of code 
for the Cisco VPN 3000 series concentrators and Cisco VPN 3002 Hardware Client, 
version 4.0.1 and 3.6.7F, would protect against all of these documented 
vulnerabilities. 

This advisory will be posted at http://www.cisco.com/warp/public/707/cisco-sa-
20030507-vpn3k.shtml. 

Affected Products 
The Cisco VPN 3000 series concentrators are affected by these vulnerabilities. 
This series includes models 3005, 3015, 3030, 3060, 3080 and the Cisco VPN 
3002 Hardware Client.

DDTS - Description
 Affected Releases
 
CSCea77143 - enabling IPSec over TCP vulnerability
 4.0.REL

3.6.REL through 3.6.7E

3.5.x

3.1.x, 3.0.x and 2.x.x are NOT affected.
 
CSCdz15393 - malformed SSH initialization packet vulnerability
 3.6.REL through 3.6.6

3.5.x

3.1.x

3.0.x

2.x.x
 
CSCdt84906 - malformed ICMP traffic vulnerability
 3.6.REL through 3.6.7

3.5.x

3.1.x

3.0.x

2.x.x
 


These vulnerabilities do not affect the VPN Client software nor the Cisco VPN 
5000 series concentrators. No other Cisco products are currently known to be 
affected by these vulnerabilities. 

To determine if a Cisco VPN 3000 series concentrator is running affected 
software, check the software revision via the web interface or the console 
menu. 

Details 
DDTS - Description
 Details
 
CSCea77143 - enabling IPSec over TCP vulnerability
 Enabling IPSec over TCP for a port on the VPN 3000 series concentrator allows 
 TCP traffic on that port to traverse through the concentrator and reach the 
 private network.

For example, if one configures IPSec over TCP to use port 80 and the private 
network is routable to from the public network i.e. a workstation on the 
public network has the VPN 3000 series concentrator configured as the gateway 
for the private network IP address space, one can browse the web servers on 
the private network configured to serve port 80 from the workstation on the 
public network without any form of authentication. Another example, if IPSec 
over TCP was not configured for port 80 but was configured for its default 
port of 10000 and if there was a server listening for telnet connections on 
port 10000 on the private network, then one could telnet to that server from 
the workstation on the public network.

For more information on IPSec over TCP please refer to the documentation 
available at 
http://www.cisco.com/univercd/cc/td/doc/product/vpn/vpn3000/4_0/config/
   tunnel.htm#1279809 
 
CSCdz15393 - malformed SSH initialization packet vulnerability
 A malformed SSH initialization packet sent during the initial SSH session 
 setup may reload the VPN 3000 series concentrator.
 
CSCdt84906 - malformed ICMP traffic vulnerability
 A flood of malformed ICMP packets could result in performance degradation on 
 the VPN 3000 series concentrator and may even cause the concentrator to reload.
 

These vulnerabilities are documented in the Cisco Bug Toolkit ( registered 
customers only) as Bug IDs CSCea77143, CSCdz15393, and CSCdt84906, and can be 
viewed after 2003 May 8 at 1600 UTC. To access this tool, you must be a 
registered user and you must be logged in.

The Inter networking Terms and Cisco Systems Acronyms online guides can be 
found at: 
http://www.cisco.com/univercd/cc/td/doc/cisintwk/. 


Impact 

DDTS - Description
 Impact
 
CSCea77143 - enabling IPSec over TCP vulnerability
 Unintended access to the private network on the VPN 3000 series concentrator. 
 This vulnerability enables one to access internal hosts on the IPSec over TCP 
 configured ports.
 
CSCdz15393 - malformed SSH initialization packet vulnerability
 This vulnerability can be exploited to initiate a Denial of Service on the 
 VPN 3000 series concentrator.
 
CSCdt84906 - malformed ICMP traffic vulnerability
 This vulnerability may cause a performance degradation on the VPN 3000 series 
 concentrator and may even result in a Denial of Service.
 


Software Versions and Fixes 
DDTS - Description
 Fixed Releases
 
CSCea77143 - enabling IPSec over TCP vulnerability
 4.0.1 and later

3.6.7F and later

3.1.x, 3.0.x and 2.x.x are NOT affected
 
CSCdz15393 - malformed SSH initialization packet vulnerability
 4.0.REL and later

3.6.7 and later
 
CSCdt84906 - malformed ICMP traffic vulnerability
 4.0.REL and later

3.6.7A and later
 

The procedure to upgrade to the fixed software version is detailed at 
http://www.cisco.com/univercd/cc/td/doc/product/vpn/vpn3000/.

Obtaining Fixed Software 
Cisco is offering free software upgrades to address these vulnerabilities for 
all affected customers. Customers may only install and expect support for the 
feature sets they have purchased. By installing, downloading, accessing or 
otherwise using such software upgrades, Customers agree to be bound by the 
terms of Cisco's software license terms found at 
http://www.cisco.com/public/sw-license-agreement.html, or as otherwise set 
forth at the Cisco Connection Online Software Center at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Customers with service contracts should contact their regular update channels 
to obtain the free software upgrade identified via this advisory. For most 
customers with service contracts, this means that upgrades should be obtained 
through the Software Center on Cisco's worldwide website at 
http://www.cisco.com/tacpage/sw-center/vpn/3000/ . 
To access the software download URL, you must be a registered user and you 
must be logged in.

Customers whose Cisco products are provided or maintained through prior or 
existing agreement with third-party support organizations such as Cisco 
Partners, authorized resellers, or service providers should contact that 
support organization for assistance with the upgrade, which should be free 
of charge.

Customers who purchase direct from Cisco but who do not hold a Cisco service 
contract and customers who purchase through third-party vendors but are 
unsuccessful at obtaining fixed software through their point of sale should 
get their upgrades by contacting the Cisco Technical Assistance Center (TAC). 
TAC contacts are as follows. 

+1 800 553 2447 (toll free from within North America) 

+1 408 526 7209 (toll call from anywhere in the world) 

e-mail: tac@cisco.com 

Please have your product serial number available and give the URL of this 
notice as evidence of your entitlement to a free upgrade. Free upgrades 
for non-contract customers must be requested through the TAC. 

Please do not contact either "psirt@cisco.com" or "security-alert@cisco.com" 
for software upgrades. 

Workarounds 
The Cisco PSIRT recommends that affected users upgrade to a fixed software 
version of code.

DDTS - Description
 Workaround
 
CSCea77143 - enabling IPSec over TCP vulnerability
 Add rules, to the filter for the private interface, that restrict outgoing 
 traffic on ports configured for use by IPSec over TCP on the VPN concentrator. 
 This would not stop the traffic from the public network reaching the VPN 3000 
 concentrator itself but would prevent the traffic from reaching the servers 
 on the private network.
 
CSCdz15393 - malformed SSH initialization packet vulnerability
 Restrict access to the SSH server on the VPN 3000 series concentrator by 
 applying appropriate rules to the filters for the interfaces such that 
 connections are permitted only from trusted client hosts.
 
CSCdt84906 - malformed ICMP traffic vulnerability
 Only allow legitimate ICMP traffic to reach the VPN 3000 series 
 concentrator's interface.
 

Exploitation and Public Announcements 
The Cisco PSIRT is not aware of any public announcements or malicious use of 
the vulnerabilities described in this advisory. 

These vulnerabilities were reported to PSIRT by internal development testing. 

The Cisco PSIRT is not aware of any public announcements or malicious use of 
the vulnerability described in this advisory. 

Status of This Notice: FINAL 
This is a final advisory. Although Cisco cannot guarantee the accuracy of all 
statements in this advisory, all of the facts have been checked to the best of 
our ability. Cisco does not anticipate issuing updated versions of this 
advisory unless there is some material change in the facts. Should there be 
a significant change in the facts, Cisco will update this advisory. 

A stand-alone copy or paraphrase of the text of this security advisory that 
omits the distribution URL in the following section is an uncontrolled copy, 
and may lack important information or contain factual errors. 

Distribution 
This advisory will be posted on Cisco's worldwide website at 
http://www.cisco.com/warp/public/707/cisco-sa-20030507-vpn3k.shtml. 

In addition to worldwide web posting, a text version of this notice is 
clear-signed with the Cisco PSIRT PGP key and is posted to the following 
e-mail and Usenet news recipients.

cust-security-announce@cisco.com

bugtraq@securityfocus.com 

first-teams@first.org (includes CERT/CC) 

cisco@spot.colorado.edu 

comp.dcom.sys.cisco 

firewalls@lists.gnac.com 

Various internal Cisco mailing lists 

Future updates of this advisory, if any, will be placed on Cisco's worldwide 
website, but may or may not be actively announced on mailing lists or 
newsgroups. Users concerned about this problem are encouraged to check the 
above URL for any updates. 

Revision History 
Revision 1.0
 2003-May-7
 Initial public release.
 
Revision 1.1
 2003-May-7
 Corrected the Affected Products table.
 
Revision 1.2
 2003-May-8
 Corrected the link in the Obtaining Fixed Software section.
 

Cisco Security Procedures 
Complete information on reporting security vulnerabilities in Cisco products, 
obtaining assistance with security incidents, and registering to receive 
security information from Cisco, is available on Cisco's worldwide website at 
http://www.cisco.com/warp/public/707/sec_incident_response.shtml. This 
includes instructions for press inquiries regarding Cisco security notices. 
All Cisco security advisories are available at http://www.cisco.com/go/psirt. 

--------------------------------------------------------------------------------

This notice is Copyright 2003 by Cisco Systems, Inc. This notice may be 
redistributed freely after the release date given at the top of the text, 
provided that redistributed copies are complete and unmodified, and include 
all date and version information. 

[***** End Cisco Security Advisory *****]

_______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Cisco for the 
information contained in this bulletin.
_______________________________________________________________________________


CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.

CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
    Voice:    +1 925-422-8193 (7x24)
    FAX:      +1 925-423-8002
    STU-III:  +1 925-423-2604
    E-mail:   ciac@ciac.org

Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.

   World Wide Web:      http://www.ciac.org/
   Anonymous FTP:       ftp.ciac.org

PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins.  If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.

This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
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otherwise, does not necessarily constitute or imply its endorsement,
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Government or the University of California, and shall not be used for
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