Summary

• A vulnerability in the certificate generation process in the admin web interface of the Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to execute arbitrary commands on an affected system with root-level privileges.
  
  The vulnerability is due to the improper validation of parameters passed to the affected system scripts. An attacker could exploit this vulnerability by passing arbitrary commands as arguments to the affected fields of the web interface. An exploit could allow the attacker to run arbitrary commands on the underlying system with root-level privileges.
  
  Cisco has released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are not available. This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-wsa

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco AsyncOS for the WSA versions 8.0 and later, both virtual and hardware versions. To determine whether a vulnerable version of Cisco IronPort AsyncOS Software for Cisco Web Security is running on an appliance, administrators can issue the version command. The following example shows a device running Cisco IronPort AsyncOS Software version 7.5.1-079:
  
  

  ciscowsa> version
  Current Version
  ===============
  Product: Cisco IronPort S670 Web Security Appliance
  Model: S670
  Version: 7.5.1-079

  Products Confirmed Not Vulnerable

  The following products are not affected by this vulnerability:
  

  • Cisco Email Security Appliance (ESA), both virtual and hardware versions
  • Cisco Security Mail Appliance (SMA), both virtual and hardware versions

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

Workarounds

• No workarounds are available.

Fixed Software

• When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories 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.
  
  

  In the following table, the left column lists major releases of Cisco AsyncOS for WSA Software. The center column indicates whether a major release is affected by the vulnerability described in this advisory and the first minor release that includes the fix for this vulnerability. The right column indicates whether a major release is affected by all the vulnerabilities described in this and the following companion advisories and which release includes fixes for those vulnerabilities:
  

  • cisco-sa-20151104-aos
  • cisco-sa-20151104-wsa
  • cisco-sa-20151104-wsa1
  • cisco-sa-20151104-wsa2
  • cisco-sa-20150612-esa
  • cisco-sa-20151104-esa2

  Customers should upgrade to an appropriate release as indicated in the following table:
  
  

  Cisco AsyncOS for WSA Major Release	First Fixed Release for This Vulnerability	First Fixed Release for This Vulnerability and All Vulnerabilities Described in the Companion Advisories
  Prior to 7.7	Not affected	7.7.0-761 or later
  7.7	Not affected	7.7.0-761
  8.0	8.0.8-113	8.0.8-113 or later
  8.1	Affected; migrate to 8.5.3-051 or later	Affected; migrate to 8.5.3-051 or later
  8.5	8.5.3-051	8.5.3-051 or later
  8.6	Affected; migrate to 8.7.0-171-LD or later	Affected; migrate to 8.7.0-171-LD or later
  8.7	8.7.0-171-LD	8.7.0-171-LD or later
  8.8	8.8.0-085	8.8.0-085 or later
  9.0	Not affected	Not affected

  
  

  In most cases a WSA can be updated over the network by using the System Upgrade options in the System Administration GUI. To upgrade a device by using the System Administration GUI:

  1. Choose System Administration > System Upgrade.
  2. Click Upgrade Options.
  3. Choose the option to Download and Install or, for an ESA, Download the upgrade.
  4. Choose the release to upgrade to.
  5. In the Upgrade Preparation area, choose the appropriate options.
  6. Click Proceed to begin the upgrade. A progress bar displays the status of the upgrade.

  After the upgrade is complete, the device reboots.

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 found during an internal security test.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151104-wsa

Revision History

• Version	Description	Section	Status	Date
  1.1	Added steps for upgrading a device by using the GUI.	Fixed Software	Final	2015-November-20
  1.0	Initial public release.	-	Final	2015-November-04

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