Summary

• A vulnerability in Advanced Malware Protection (AMP) for Cisco Email Security Appliances (ESA) and Web Security Appliances (WSA) could allow an unauthenticated, remote attacker to cause a partial denial of service (DoS) condition due to the AMP process unexpectedly restarting.
  
  The vulnerability is due to improper validation of a Java Archive (JAR) file that is scanned when AMP is configured. An attacker could exploit this vulnerability by crafting a JAR file and attaching this JAR file to an email that is then sent through the ESA, or allowing the JAR file to be download from the web through the WSA. An exploit could allow the attacker to cause the Cisco ESA and WSA AMP process to unexpectedly restart due to the malformed JAR file.
  
  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-20161026-esawsa3

Affected Products

• Vulnerable Products

  The following products are affected:
  

  • Cisco AsyncOS Software for Email Security Appliances (ESA) versions 9.5 and later up to the first fixed release
  • Cisco AsyncOS Software for Web Security Appliances (WSA) all versions prior to the first fixed release

  To determine which release of Cisco AsyncOS Software is running on an ESA, administrators can use the version command in the CLI. The following example shows the output of the version command for an ESA running Cisco AsyncOS Software Release 8.5.7-044:
  

  ciscoesa> version
  
  Current Version
  ===============
  Product: Cisco IronPort X1070 Messaging Gateway(tm) Appliance
  Model: X1070
  Version: 8.5.7-044
  .
  .
  .

  Note that Cisco provides regular maintenance of products in the Cisco Cloud Email Security (CES) service solution, which includes Cisco Email Security Appliances and Cisco Content Security Management Appliances. Customers can also request a software upgrade by contacting Cisco CES support.
  
  To determine whether a vulnerable version of Cisco AsyncOS Software is running on a Cisco WSA, administrators can use the version command in the WSA CLI. The following example shows the results for an appliance running Cisco AsyncOS Software version 8.5.3-051:
  
  

  ciscowsa> version
  
  Current Version
  
  ===============
  
  Product: Cisco IronPort S670 Web Security Appliance
  
  Model: S670
  
  Version: 8.5.3-051
  
  .
  
  .
  
  .

  
  

  Products Confirmed Not Vulnerable

  The following products are not vulnerable:
  

  • Content Security Management Appliance
  • FireSIGHT System Software
  • AnyConnect Secure Mobility Client for iOS
  • AnyConnect Secure Mobility Client for Mac OS X
  • AnyConnect Secure Mobility Client for Android
  • AnyConnect Secure Mobility Client for Windows
  • AnyConnect Secure Mobility Client for Linux

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

Indicators of Compromise

• Exploitation of this vulnerability could cause the malformed JAR file to be marked as UNSCANNABLE and the following error logged:
  
  <Date> Info: MID <####> AMP file reputation verdict : UNSCANNABLE
  
  The ESA and WSA could also write out a core file for the AMP process. Contact the Cisco Technical Assistance Center (TAC) to review the core file and confirm if the core file shows that the device has been compromised by this vulnerability.

Workarounds

• Workarounds that address this vulnerability are not available.

Fixed Software

• Cisco provides information about fixed software in Cisco bugs, which are accessible through the Cisco Bug Search Tool.
  
  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 be upgraded 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.

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 resolution of a support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161026-esawsa3

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the Summary.	Summary	Final	2016-October-31
  1.0	Initial public release.	—	Final	2016-October-26

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