[hidden]

Cisco IPSec VPN Services Module Denial of Service
Release Date: 2004-04-09
Critical: Moderately critical
Impact: DoS
Where: From remote

Software: Cisco IPSec VPN Services Module

Summary
The Cisco IP Security (IPSec) VPN Services Module (VPNSM) is a high-speed module for the Cisco Catalyst 6500 Series Switch and the Cisco 7600 Series Internet Router that provides infrastructure-integrated IPSec VPN services.

A malformed Internet Key Exchange (IKE) packet may cause the Cisco Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router hardware, with the VPNSM installed, to crash and reload.

This vulnerability is documented as Cisco bug ID CSCed30113. There is no workaround available to mitigate the effects of this vulnerability. Cisco is providing fixed software at no charge, and recommends that customers upgrade to it.

This advisory will be posted at http://www.cisco.com...408-vpnsm.shtml.

Affected Products
Vulnerable Products
All Cisco Catalyst 6500 Series Switch and the Cisco 7600 Series Internet Router hardware, with the VPNSM installed, running the following Cisco IOS releases are affected by this vulnerability:

Release Train
Affected Releases

12.2SXA
earlier than 12.2(17b)SXA

12.2SXB
earlier than 12.2(17d)SXB

12.2SY
earlier than 12.2(14)SY03



Products Confirmed Not Vulnerable
Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Internet Router hardware, using the VPNSM and running Cisco IOS release train 12.1E are not affected by this vulnerability.

No other Cisco products are currently known to be affected by this vulnerability.

To determine your software revision, type show version at the command line prompt.

Details
A malformed IKE packet may cause the Cisco Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router hardware, with the VPNSM installed, to crash and reload.

This vulnerability could be used to conduct a Denial of Service (DoS) attack on the Cisco Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router hardware platforms that have the VPNSM installed in them. This vulnerability is known to only exist in the modified IKE code which was incorporated in the 12.2SXA, 12.2SXB and 12.2SY Cisco IOS software release trains.

More information on the VPNSM is available at http://www.cisco.com...00800c4fe2.html.

The Internetworking Terms and Cisco Systems Acronyms online guides can be found at http://www.cisco.com...d/doc/cisintwk/.

This vulnerability is documented in the Cisco Bug Toolkit as Bug ID CSCed30113 ( registered customers only) .

Impact
This vulnerability could be used to conduct a Denial of Service (DoS) attack on the Cisco Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router hardware platforms that have the VPNSM installed in them.

Software Versions and Fixes
This vulnerability has been fixed in the following Cisco IOS releases for the Cisco Catalyst 6500 Series Switch and the Cisco 7600 Series Internet Router hardware:

Release Train
Fixed Releases

12.2SXA
12.2(17b)SXA and later

12.2SXB
12.2(17d)SXB and later

12.2SY
12.2(14)SY03 and later



Please refer to these documents for more information:

12.2(17b)SXA Release Notes: http://www.cisco.com...00801df1dd.html

12.2(17d)SXB Release Notes: http://www.cisco.com...00802078b5.html

12.2(14)SY03 Release Notes: http://www.cisco.com...0801ab5a3.shtml

Obtaining Fixed Software
Cisco is offering free software upgrades to address this vulnerability for all affected customers.

Customers with Service Contracts
Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com...2.2/index.shtml.

Customers using Third-party Support Organizations
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 without Service Contracts
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.

See http://www.cisco.com...ry/DirTAC.shtml for additional TAC contact information, including special localized telephone numbers and instructions and e-mail addresses for use in various languages.

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...-agreement.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com...-usingswc.shtml.

Workarounds
There is no workaround for this vulnerability. The Cisco PSIRT recommends that affected users upgrade to a fixed software version of code.

As a possible mitigation, users deploying the VPNSM for site to site connectivity could apply ACLs on the Cisco Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router to limit the IP addresses that can establish IPSec sessions with the VPNSM.

Exploitation and Public Announcements
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

This vulnerability was reported to Cisco PSIRT by a customer.

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 may update this advisory.

Note: 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...408-vpnsm.shtml.

In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key having the fingerprint 8C82 5207 0CA9 ED40 1DD2 EE2A 7B31 A8CF 32B6 B590 and is posted to the following e-mail and Usenet news recipients.

cust-security-announce@cisco.com

first-teams@first.org (includes CERT/CC)

bugtraq@securityfocus.com

vulnwatch@vulnwatch.org

cisco@spot.colorado.edu

cisco-nsp@puck.nether.net

full-disclosure@lists.netsys.com

comp.dcom.sys.cisco@newsgate.cisco.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 1.1
2004-April-8
Removed 12.2ZA as a vulnerable Cisco IOS software release train.

Revision 1.0
2004-April-8
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..._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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[packet]

This is why I like to have my switches do switching and have a dedicated VPN device just for VPNs. Anyone out there actually use the module? I haven't seen it anywhere yet.

--P>G>>