Cisco Security Advisory-
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 https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20020812-vpnclient-vulnerability.
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This section provides details on affected products.
Vulnerable Products
The VPN Client software program runs on the following platforms:
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Microsoft Windows-based PC.
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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.
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Solaris UltraSPARC running a 32-bit kernel OS Version 2.6 or
later.
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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.
Products Confirmed Not Vulnerable
Cisco VPN 5000 Client software programs are not affected by this vulnerability.
No other Cisco products are currently known to be affected by these vulnerabilities.
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Microsoft Windows-based PC.
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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:
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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.
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An IKE packet with more than 57 valid payloads causes a buffer
overflow in the VPN Client software.
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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.
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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.
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There are no workarounds for these vulnerabilities. The Cisco PSIRT recommends that affected users upgrade to a fixed software version of code.
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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/.
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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 and were discovered by Anton Rager of Avaya Security Consulting Services.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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