Cisco Security Advisory: Cisco Secure Desktop ActiveX Control Code Execution Vulnerability



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Cisco Security Advisory: Cisco Secure Desktop ActiveX Control Code
Execution Vulnerability

Advisory ID: cisco-sa-20100414-csd

Revision 1.0

+---------------------------------------------------------------------

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://www.cisco.com/warp/public/707/cisco-sa-20100414-csd.shtml

Affected Products
=================

Vulnerable Products
+------------------

Cisco Secure Desktop versions prior to 3.5.841 are affected.

Products Confirmed Not Vulnerable
+--------------------------------

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

Details
=======

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 and has been assigned the Common Vulnerabilities and
Exposures (CVE) ID CVE-2010-0589.

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

CSCta25876

CVSS Base Score - 9.3

Access Vector - Network
Access Complexity - Medium
Authentication - None
Confidentiality Impact - Complete
Integrity Impact - Complete
Availability Impact - Complete

CVSS Temporal Score - 7.7

Exploitability - Functional
Remediation Level - Official-Fix
Report Confidence - Confirmed

Impact
======

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

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.

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@xxxxxxxxx

Workarounds
===========

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.

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://www.cisco.com/warp/public/707/cisco-amb-20100414-csd.shtml

Obtaining Fixed Software
========================

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@xxxxxxxxx or security-alert@xxxxxxxxx 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@xxxxxxxxx

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 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.

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://www.cisco.com/warp/public/707/cisco-sa-20100414-csd.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.

* cust-security-announce@xxxxxxxxx
* first-bulletins@xxxxxxxxxxxxxxx
* bugtraq@xxxxxxxxxxxxxxxxx
* vulnwatch@xxxxxxxxxxxxx
* cisco@xxxxxxxxxxxxxxxxx
* cisco-nsp@xxxxxxxxxxxxxxx
* full-disclosure@xxxxxxxxxxxxxxxxx
* comp.dcom.sys.cisco@xxxxxxxxxxxxxxxxxx

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 | | Initial |
| 1.0 | 2010-April-14 | 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/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
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