N-093: Cisco VPN 3000 Concentrator Vulnerabilities
Privacy and Legal Notice
INFORMATION BULLETIN
N-093: Cisco VPN 3000 Concentrator Vulnerabilities
[Cisco Security Advisory]
May 8, 2003 16:00 GMT
|
| 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
ASSESSMENT: |
The risk is MEDIUM. A flood of malformed ICMP packets could
result in performance degradation. Under certain configurations,
an attacker could telnet to a server from a workstation on a
public network.
|
|
[***** 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)
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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
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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#1279
809
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.
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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 *****]
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