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Cisco Content Delivery System Internet Streamer: Web Server Vulnerability

Advisory ID: cisco-sa-20110525-spcdn

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-spcdn

Revision 1.0

For Public Release 2011 May 25 16:00  UTC (GMT)


Summary

The Cisco Internet Streamer application, part of the Cisco Content Delivery System (Cisco CDS), contains a vulnerability in its web server component that could cause the web server engine to crash when processing specially crafted URLs.

Cisco has released free software updates that address this vulnerability.

Workarounds that mitigate this vulnerability are not available.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-spcdn.

Affected Products

System software versions 2.5.7 and later on the Cisco Internet Streamer application are vulnerable prior to the first fixed release. System software versions prior to 2.5.7 are not affected by this vulnerability.

Vulnerable Products

To determine the software version that is running on a Cisco Content Delivery Engine, log in to the device and issue the show version command-line interface (CLI) command to display the system banner. Cisco CDS Internet Streamer software will identify itself as "Content Delivery System Software Release". On the same line of output, the version number will also be provided. This example identifies a Cisco Content Delivery Engine that is running Cisco Content Delivery System software release 2.5.9 build 5:

cdn-cde#show version
Content Delivery System Software (CDS)
Copyright (c) 1999-2010 by Cisco Systems, Inc.
Content Delivery System Software Release 2.5.9 (build b5 Jun 16 2010)
Version: cde200-2.5.9.5

Compiled 22:10:04 Jun 16 2010 by ipvbuild
Compile Time Options: KQ SS

System was restarted on Wed Sep 15 06:50:22 2010.
The system has been up for 1 hour, 25 minutes, 6 seconds.

cdn-cde#

Alternatively, the Content Delivery System Manager home page gives a brief summary of the software versions in use on all the devices in the content delivery system network.

To view the software version running on a particular device, choose Devices > Devices. The Devices Table page displays the software version for each device listed. For further information on finding the software version, refer to "Maintaining the Internet Streamer CDS" at the following link: http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/configuration_guide/maint.html#wp1198510.

Products Confirmed Not Vulnerable

Cisco Content Delivery Engines running TV streaming content delivery applications and the Video Navigator application are not affected.

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

Details

The Cisco Internet Streamer application provides edge caching, content streaming, and downloads to subscriber IP devices such as PCs.

The Cisco Internet Streamer application, part of the Cisco CDS, contains a vulnerability on its web server component that could cause the web server engine to crash when processing specially crafted URLs.

An unauthenticated attacker may be able to exploit this vulnerability to cause a denial of service condition on the web server that is running on the Service Engine. The device will remain operational, and the Web Engine will restart if the attack stops.

This vulnerability is documented in the Cisco Bug IDs CSCtg67333 ( registered customers only) and CSCth25341 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-1649. Both bugs fixes are required for a full solution.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html .

Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss .


CSCtg67333 / CSCth25341 Crafted URL may crash webengine in CDS Internet Streamer

Calculate the environmental score of CSCtg67333/CSCth25341

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

Impact

Successful exploitation of the vulnerability may cause the Web Engine of the Cisco Internet Streamer application to crash.

The device will remain operational, and the Web Engine will restart if the attack stops.

A sustained attack will prevent the distribution of HTML content to end users.

Software Versions and Fixes

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.

The recommended release contains other software fixes that are recommended by Cisco. For further information please consult the Release Notes for Cisco Internet Streamer CDS 2.5.9 at the following link: http://www.cisco.com/en/US/docs/video/cds/cda/is/2_5/release_notes/CDS_RelNotes2_5_9.html#wp100128

Cisco Content Delivery System Software Release

First Fixed Release

Recommended Release

2.2.x

Not Vulnerable

2.3.x

Not Vulnerable

2.4.x

Not Vulnerable

2.5.x

Releases prior to 2.5.7 are not affected, first fixed in 2.5.9 build 126

2.5.9 build 126

Workarounds

There are no workarounds for the vulnerability documented in this security advisory.

Obtaining Fixed Software

Cisco has released free software updates that address these vulnerabilities. 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/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .

Do not contact psirt@cisco.com or security-alert@cisco.com for software upgrades

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.

Customers using Third Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix 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 or fix is the most appropriate for use in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.

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 discovered when handling customer support calls.

Status of this Notice: Final

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.


Distribution

This advisory is posted on Cisco's worldwide website at:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110525-spcdn

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.

  • cust-security-announce@cisco.com
  • first-teams@first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@newsgate.cisco.com

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

2011-May-25

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/web/about/security/psirt/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.