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Cisco Security Advisory: Cisco VPN Client Multiple Vulnerabilities
Revision 1.0
For Public Release 2002 August 12 UTC 1500
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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
Distribution
Revision History
Cisco Security Procedures
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Summary
Multiple vulnerabilities exist in the Cisco Virtual Private Network (VPN)
Client software. Exploitation of these vulnerabilities prevents the Cisco
VPN Client software program from functioning correctly.
These vulnerabilities are documented as Cisco bug ID CSCdy26045. There are
no workarounds available to mitigate the effects of these vulnerabilities.
This advisory will be posted at
http://www.cisco.com/warp/public/707/vpnclient-multiple-vuln-pub.shtml.
Affected Products
The VPN Client software program runs on the following platforms:
* Microsoft Windows-based PC.
* Red Hat Version 6.2 Linux (Intel), or compatible distribution, using
kernel Version 2.2.12 or later. It does not support kernel Version
2.5.
* Solaris UltraSPARC running a 32-bit kernel OS Version 2.6 or later.
* Mac OS X Version 10.1.0 or later.
All VPN Client software programs, earlier than version 3.6 and earlier
than version 3.5.4, on all platforms are affected by this vulnerability.
This includes the previous Cisco Secure VPN Client and the the Cisco VPN
3000 Client software programs.
Cisco VPN 5000 Client software programs are not affected by this
vulnerability.
No other Cisco product is currently known to be affected by this
vulnerability.
Details
The VPN Client software program on a remote workstation, communicating
with a Cisco VPN device on an enterprise network or with a service
provider, creates a secure connection over the Internet. Through this
connection you can access a private network as if you were an on-site
user.
The VPN Client software program has been found to have the following
vulnerabilities:
* An Internet Key Exchange (IKE) packet with a Security Parameter Index
(SPI) payload containing more than 16 bytes causes a buffer overflow
in the VPN client software.
* An IKE packet with more than 57 valid payloads causes a buffer
overflow in the VPN Client software.
* When the VPN Client software receives a specially crafted packet with
a zero length payload, it causes the VPN Client software to use 100%
of CPU resources on the workstation.
These vulnerabilities are documented as Cisco bug ID CSCdy26045, which
requires a CCO account to view. CSCdy26045 can be viewed after 2002 August
13 at 1500 UTC.
Impact
When the vulnerabilities are exploited they prevent the Cisco VPN Client
software program from functioning correctly. The Cisco VPN Client software
program's availability may be impacted. There is no impact to the
confidentiality and integrity of the data.
Software Versions and Fixes
This vulnerability has been fixed in Cisco VPN Client version 3.6 or
later, which is now available for download. The fix for this vulnerability
will also be integrated in VPN Client version 3.5.4 or later, and will be
available for download by September 30, 2002.
The procedure to upgrade to the fixed software version on the various
platforms is detailed in the documentation available at
http://www.cisco.com/univercd/cc/td/doc/product/vpn/client/.
Obtaining Fixed Software
Cisco is offering free software upgrades to address this vulnerability for
all affected customers. Customers may only install and expect support for
the feature sets they have purchased.
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/kobayashi/sw-center/.
Customers whose Cisco products are provided or maintained through a 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 obtaining the free software
upgrade(s).
Customers who purchased directly 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 obtain fixed software by contacting the Cisco Technical
Assistance Center (TAC) using the contact information listed below. In
these cases, customers are entitled to obtain an upgrade to a later
version of the same release or as indicated by the applicable corrected
software version in the Software Versions and Fixes section (noted above).
Cisco 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
See http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for
additional TAC contact information, including special localized telephone
numbers and instructions and e-mail addresses for use in various
languages.
Please have your product serial number available and give the URL of this
advisory as evidence of your entitlement to a free upgrade.
Please do not contact either "psirtat_private" or
"security-alertat_private" for software upgrades.
Workarounds
There are no workarounds for these vulnerabilities. The Cisco PSIRT
recommends that affected users upgrade to a fixed software version of
code.
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 CERT/CC.
Status of This Notice: FINAL
This is a final notice. 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 may 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/vpnclient-multiple-vuln-pub.shtml.
In addition to worldwide website posting, a text version of this advisory
is clear-signed with the Cisco PSIRT PGP key having the fingerprint FEB1
1B89 A64B 60BB 4770 D1CE 93D2 FF06 F236 759C and is posted to the
following e-mail and Usenet news recipients:
* cust-security-announceat_private
* bugtraqat_private
* full-disclosureat_private
* first-teamsat_private (includes CERT/CC)
* firewallsat_private
* cisco-nspat_private
* ciscoat_private
* comp.dcom.sys.cisco
* 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 | 2002-August-12 | 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/go/psirt. This includes instructions for
press inquiries regarding Cisco security advisories.
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This notice is Copyright 2002 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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