__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Capability
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__________________________________________________________
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
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FAX: +1 925-423-8002
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E-mail: ciac@ciac.org
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This document was prepared as an account of work sponsored by an
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employees, makes any warranty, express or implied, or assumes any
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