Summary
Affected Products
Details
Impact
Software Versions and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of This Notice: FINAL
Distribution
Revision History
Cisco Security Procedures
Cisco CSS 11500 Series Content Services Switches (CSS) configured with Secure Socket Layer (SSL) termination services are vulnerable to a Denial of Service (DoS) attack when processing malformed client certificates. Cisco has made free software available to address this vulnerability. There are workarounds available to mitigate the effects of the vulnerability.
This advisory is posted at http://www.cisco.com/warp/public/707/cisco-sa-20051019-css.shtml.
This section provides details on affected products.
Cisco CSS 11500 Series Content Services Switches running the following versions of the Cisco WebNS operating system:
The version of Cisco WebNS running on a CSS can be determined by running the following command:
# show version
Cisco CSS 11000 Series Content Services Switches
No other Cisco products are currently known to be affected by these vulnerabilities.
The Cisco CSS 11500 Content Service Switch is load balancing device designed to provide robust, scalable network services (Layer 4-7) for data centers. The Cisco CSS 11500 performs an analysis of protocol headers and directs requests to an appropriate resource based on configurable policies. With integrated SSL modules, a Cisco CSS 11500 can simplify the management of digital cerfiticates and provide SSL acceleration services to optimize performance.
A Cisco CSS 11500 may reload due to a memory corruption issue when presented with a malformed digital client certificate during the negotiation of a SSL session. This condition is present even if the CSS did not request a client certificate during SSL session negotiations. This vulnerability is only present if a CSS is configured to support SSL termination services. SSL termination services are not configured by default.
Users can determine if SSL termination services are configured on a CSS by performing the following steps.
# show running-config
service ssl-serv1
type ssl-accel
slot 3
keepalive type none
add ssl-proxy-list ssl list1
active
The vulnerability is documented in the following Cisco Bug ID:
Successful exploitation of the vulnerability may result in the immediate reload of the device. Repeated exploitation could result in a sustained DoS attack.
When considering software upgrades, consult http://www.cisco.com/en/US/products/products_security_advisories_listing.html and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") for assistance.
|
Train |
Fixed Releases |
|---|---|
|
7.3 |
7.30.4.02 and later |
|
7.4 |
7.40.2.02 and later |
|
7.5 |
7.50.1.03 and later |
Customers running Cisco WebNS 7.10 and 7.20 are encouraged to upgrade CSS platforms to a fixed version of Cisco WebNS 7.30 or greater. Fixed software may be obtained by registered users at http://www.cisco.com/pcgi-bin/tablebuild.pl/css11500-maint?psrtdcat20e2.
The effectiveness of any workaround is dependent on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround is the most appropriate for use in the intended network before it is deployed.
If upgrading to a fixed version of Cisco WebNS software is not possible, the following workarounds are available.
Documentation for configuring SSL services on a CSS running Cisco WebNS 7.40 can be found at http://www.cisco.com/en/US/products/hw/contnetw/ps792/products_configuration_guide_book09186a008027ab4e.html.(config)# no service ssl-serv1 Delete service <ssl>, [y/n]:y
Cisco has made free software available to address this vulnerability for affected customers. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.
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 Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.
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.
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.
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.
Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.
Refer to 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.
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 Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.
This advisory is posted on Cisco's worldwide website at http://www.cisco.com/warp/public/707/cisco-sa-20051019-css.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.
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 1.1 |
2005-October-19 |
Added direct links to fixed software in Software Versions and Fixes table. |
|
Revision 1.0 |
2005-October-19 |
Initial public release. |
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/en/US/products/products_security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.
All contents are Copyright © 2006-2007 Cisco Systems, Inc. All rights reserved. Important Notices and Privacy Statement.
| Updated: Oct 19, 2005 | Document ID: 67919 |