Cisco Security Advisory-
Cisco CSS 11500 Series Content Services Switches configured for Hyper Text Transfer Protocol (HTTP) compression are vulnerable to a Denial of Service (DoS) attack when processing valid, but obsolete, or specially crafted HTTP request.
Cisco has made free software available to address this vulnerability for affected customers. The workaround is to disable HTTP compression.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20060405-css.
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This section provides details on affected products.
Vulnerable Products
Cisco CSS 11500 Series Content Services Switches that are configured for HTTP compression are vulnerable.
A Cisco CSS11500 that is configured for HTTP compression will have configuration similar to the following, which can be seen by issuing the show running-config command:
service compression_service_name .... .... compress enable .... ....Products Confirmed Not Vulnerable
Cisco CSS 11500 Series Content Services Switches that are not configured for HTTP compression are not vulnerable.
No other Cisco products are currently known to be affected by these vulnerabilities.
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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 a compression module, a Cisco CSS 11500 can compress HTTP client traffic.
For more information about HTTP compression on CSS 11500 switches, refer to the following URL:
A Cisco CSS 11500 enabled for HTTP compression may reload after receiving valid, but obsolete, or specially crafted HTTP request.
Cisco CSS 11500 switches where HTTP compression is not used or is disabled are not affected by this vulnerability.
The vulnerability is documented in the following Cisco Bug ID:
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CSCek24160
(
registered customers only)
--CSS cores while using software compression.
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CSCek24160
(
registered customers only)
--CSS cores while using software compression.
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The workaround is to disable HTTP compression. That can be accomplished using the compress disable command.
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When considering software upgrades, also consult http://www.cisco.com/go/psirt 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") or your contracted maintenance provider for assistance.
This issue is fixed in version 8.10.1.6 of CSS software. Fixed software can be downloaded from the following URL::
http://www.cisco.com/pcgi-bin/tablebuild.pl/css11500-maint?psrtdcat20e2
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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 by a customer.
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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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