Cisco Security Advisory

Advisory ID: cisco-sa-20100414-csd

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20100414-csd

Revision 1.1

For Public Release 2010 April 14 16:00  UTC (GMT)

Summary

Cisco Secure Desktop contains a vulnerable ActiveX control that could allow an attacker to execute arbitrary code with the privileges of the user who is currently logged into the affected system. Cisco has released a free software update that addresses this vulnerability. There is a workaround that mitigates this vulnerability.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20100414-csd.

Affected Products

A Cisco-signed ActiveX control that is used by Cisco Secure Desktop fails to properly verify the integrity of an executable file that is used by the Cisco Secure Desktop installation process. If an attacker can entice a user to visit an attacker controlled web page, the vulnerable ActiveX control could be invoked to download an attacker-modified package. The package could contain a malicious executable file that executes with the privileges of the affected user. A successful exploit could result in a complete compromise of a vulnerable system. This vulnerability is documented in Cisco Bug ID CSCta25876 ( registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2010-0589.

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

Successful exploitation of this vulnerability could result in a complete compromise of the affected system.

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.

Cisco Secure Desktop version 3.5.841 can be downloaded at the following link:

http://tools.cisco.com/support/downloads/go/ImageList.x?relVer=3.5.841&mdfid=280277835&sftType=CSD+package-+ASA+Distribution&optPlat=&nodecount=2&edesignator=null&modelName=Cisco+Secure+Desktop&treeMdfId=268438162&treeName=Security&modifmdfid=null&imname=&hybrid=&imst=&lr=Y

Note: Cisco Secure Desktop versions 3.0 and 3.1 are only supported for operation with certain versions of Cisco IOS software and Cisco Adaptive Security Appliance (ASA) software version 7.x. Cisco Secure Desktop versions 3.2 through 3.5 are only supported for operation with Cisco ASA software version 8.x. Customers running Cisco Secure Desktop versions 3.2 through 3.5 with a supported Cisco ASA software version are encouraged to upgrade to Cisco Secure Desktop version 3.5.841.

Customers with active software licenses for Cisco Secure Desktop versions 3.0 and 3.1 should send email to the following address for instructions on migrating to non-vulnerable software:

csd-activex-inquiry@cisco.com

Administrators can mitigate this vulnerability by using the kill bit feature of Microsoft Windows to prevent the loading and execution of the vulnerable ActiveX control. Administrators must use the Class identifier (CLSID) of the vulnerable ActiveX control to disable the control. The affected CLSID is:

705EC6D4-B138-4079-A307-EF13E4889A82

Instructions for setting the kill bit in Microsoft Windows are available at the following link:

http://support.microsoft.com/kb/240797

Note: Kill bit settings are permanent. The settings must be removed to regain Cisco Secure Desktop functionality. After an administrator has updated the Cisco Secure Desktop software to a fixed version on VPN portal devices, the kill bit must be removed from Microsoft Windows clients in order to allow the Cisco Secure Desktop software to be upgraded. Once the kill bit is removed, clients may be vulnerable until a fixed Cisco Secure Desktop version is installed.

Update: Cisco Secure Desktop software version 3.5.1077 replaces the old, vulnerable ActiveX CLSID with a newly issued CLSID. New installations and upgrading from an older version of Cisco Secure Desktop will use the new CLSID. Once the software upgrade has been installed on client systems, administrators can safely and permanently implement the ActiveX kill bit workaround for the old CLSID in their environment.

Additional mitigation techniques that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory:

http://tools.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20100414-csd

Cisco has released free software updates that address this vulnerability. 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 Using Third-Party Support Organizations

Customers Without Service Contracts

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

This vulnerability was discovered and reported to Cisco by an anonymous researcher working with TippingPoint's Zero Day Initiative. Cisco would like to thank TippingPoint for reporting this vulnerability and collaborating on a coordinated disclosure.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20100414-csd

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-bulletins@lists.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.

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.