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Cisco Security Advisory: Cisco VPN 3000 Concentrator Vulnerabilities
Revision 1.0
For Public Release 2003 May 7 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 |
|----------------------+-------------------|
| | * 4.0.REL |
| | |
| | * 3.6.REL through|
|CSCea77143 - enabling | 3.6.7F |
|IPSec over TCP | |
|vulnerability | * 3.5.x |
| | |
| | * 3.1.x, 3.0.x |
| | and 2.x.x are |
| | NOT affected. |
|----------------------+-------------------|
| | * 3.6.REL through|
| | 3.6.7 |
| | |
|CSCdz15393 - malformed| * 3.5.x |
|SSH initialization | |
|packet vulnerability | * 3.1.x |
| | |
| | * 3.0.x |
| | |
| | * 2.x.x |
|----------------------+-------------------|
| | * 3.6.REL through|
| | 3.6.7A |
| | |
|CSCdt84906 - malformed| * 3.5.x |
|ICMP traffic | |
|vulnerability | * 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 - | Details |
| Description | |
|--------------+---------------------------|
| |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 |
|CSCea77143 - |configured as the gateway |
|enabling IPSec|for the private network IP |
|over TCP |address space, one can |
|vulnerability |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. |
|--------------+---------------------------|
|CSCdz15393 - |A malformed SSH |
|malformed SSH |initialization packet sent |
|initialization|during the initial SSH |
|packet |session setup may reload |
|vulnerability |the VPN 3000 series |
| |concentrator. |
|--------------+---------------------------|
| |A flood of malformed ICMP |
|CSCdt84906 - |packets could result in |
|malformed ICMP|performance degradation on |
|traffic |the VPN 3000 series |
|vulnerability |concentrator and may even |
| |cause the concentrator to |
| |reload. |
+------------------------------------------+
These vulnerabilities are documented in the Cisco Bug Toolkit
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.
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
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 |
|-------------------+----------------------|
| |Unintended access to |
| |the private network on|
| |the VPN 3000 series |
|CSCea77143 - |concentrator. This |
|enabling IPSec over|vulnerability enables |
|TCP vulnerability |one to access internal|
| |hosts on the IPSec |
| |over TCP configured |
| |ports. |
|-------------------+----------------------|
|CSCdz15393 - |This vulnerability can|
|malformed SSH |be exploited to |
|initialization |initiate a Denial of |
|packet |Service on the VPN |
|vulnerability |3000 series |
| |concentrator. |
|-------------------+----------------------|
| |This vulnerability may|
|CSCdt84906 - |cause a performance |
|malformed ICMP |degradation on the VPN|
|traffic |3000 series |
|vulnerability |concentrator and may |
| |even result in a |
| |Denial of Service. |
+------------------------------------------+
Software Versions and Fixes
+------------------------------------------+
| DDTS - Description | Fixed Releases |
|------------------------+-----------------|
| | * 4.0.1 and |
| | later |
| | |
|CSCea77143 - enabling | * 3.6.7F and |
|IPSec over TCP | later |
|vulnerability | |
| | * 3.1.x, 3.0.x |
| | and 2.x.x are|
| | NOT affected |
|------------------------+-----------------|
| | * 4.0.REL and |
|CSCdz15393 - malformed | later |
|SSH initialization | |
|packet vulnerability | * 3.6.7 and |
| | later |
|------------------------+-----------------|
| | * 4.0.REL and |
|CSCdt84906 - malformed | later |
|ICMP traffic | |
|vulnerability | * 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.shtm.
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/public/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: tacat_private
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 "psirtat_private" or
"security-alertat_private" for software upgrades.
Workarounds
The Cisco PSIRT recommends that affected users upgrade to a fixed software
version of code.
+------------------------------------------+
|DDTS - Description| Workaround |
|------------------+-----------------------|
| |Add rules, to the |
| |filter for the private |
| |interface, that |
| |restrict outgoing |
| |traffic on ports |
| |configured for use by |
|CSCea77143 - |IPSec over TCP on the |
|enabling IPSec |VPN concentrator. This |
|over TCP |would not stop the |
|vulnerability |traffic from the public|
| |network reaching the |
| |VPN 3000 concentrator |
| |itself but would |
| |prevent the traffic |
| |from reaching the |
| |servers on the private |
| |network. |
|------------------+-----------------------|
| |Restrict access to the |
| |SSH server on the VPN |
|CSCdz15393 - |3000 series |
|malformed SSH |concentrator by |
|initialization |applying appropriate |
|packet |rules to the filters |
|vulnerability |for the interfaces such|
| |that connections are |
| |permitted only from |
| |trusted client hosts. |
|------------------+-----------------------|
|CSCdt84906 - |Only allow legitimate |
|malformed ICMP |ICMP traffic to reach |
|traffic |the VPN 3000 series |
|vulnerability |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-announceat_private
* bugtraqat_private
* first-teamsat_private (includes CERT/CC)
* ciscoat_private
* comp.dcom.sys.cisco
* firewallsat_private
* 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. |
+------------------------------------------+
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.
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