Summary

• A vulnerability in the Start Before Logon (SBL) module of Cisco AnyConnect Secure Mobility Client Software for Windows could allow an unauthenticated, local attacker to open Internet Explorer with the privileges of the SYSTEM user.
  
  The vulnerability is due to insufficient implementation of the access controls. An attacker could exploit this vulnerability by opening the Internet Explorer browser. An exploit could allow the attacker to use Internet Explorer with the privileges of the SYSTEM user. This may allow the attacker to execute privileged commands on the targeted system.
  
  
  Cisco has released software updates that address this vulnerability. Workarounds that address this vulnerability are not available. This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170208-anyconnect

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco AnyConnect Secure Mobility Client for Windows when configured for SBL.
  
  To verify whether the SBL feature is configured and enabled, administrators should verify that:
  

  • The Cisco AnyConnect SBL is installed on the client machine.
  • The UseStartBeforeLogon option is set to true in the Cisco AnyConnect Secure Mobility Client profile.

  
  To verify whether the Cisco AnyConnect SBL Module is installed on a machine, administrators can use the Add/Remove programs functionality in Windows and look for the presence of the Cisco AnyConnect Start Before Login Module.
  
  Note: Cisco uses the term "Start Before Logon" in the configuration and in documentation; however, the module that is installed on Windows is called the "Cisco AnyConnect Start Before Login Module." Note also that the Cisco AnyConnect Start Before Login Module is not installed by default.
  
  To verify whether UseStartBeforeLogon is set to true in the Cisco AnyConnect Secure Mobility Client profile, administrators should inspect the Cisco AnyConnect Secure Mobility Client profile XML file.
  
  The Cisco AnyConnect Secure Mobility Client profile is usually located in the C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\Profile folder.
  
  The following example shows AnyConnect Mobile Client profile xml file with UseStartBeforeLogon set to true.
  

  .
  .
  .
  

          true

  .
  .
  .

  
  Note: UseStartBeforeLogon is set to true by default.
  

  Products Confirmed Not Vulnerable

  This vulnerability does not affect Cisco AnyConnect Secure Mobility Client for Mac OS or for Linux. Additionally, this vulnerability does not affect Cisco AnyConnect Secure Mobility Client for mobile devices operating systems such as iOS, Android, and Windows Phone.
  
  No other Cisco products are currently known to be affected by this vulnerability.

Workarounds

• There are no workarounds that address this vulnerability

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
  http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html

  Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.

  When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.

  In all cases, customers should ensure that the devices to upgrade contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

  Customers Without Service Contracts

  Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
  http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html

  Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.

  Fixed Releases

  This vulnerability has been resolved in Cisco AnyConnect Secure Mobility Client for Windows Software versions 4.4.00243 and later and 4.3.05017 and later.

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

Source

• This vulnerability was reported to Cisco by Thomas Toth.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170208-anyconnect

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2017-February-08

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