Summary

• A vulnerability in the local Certificate Authority (CA) feature of Cisco ASA Software could allow an unauthenticated, remote attacker to cause a reload of the affected system.
  
  The vulnerability is due to improper handling of crafted packets during the enrollment operation. An attacker could exploit this vulnerability by sending a crafted enrollment request to the affected system. An exploit could allow the attacker to cause the reload of the affected system.
  
  Note: Only HTTPS packets directed to the Cisco ASA interface, where the local CA is allowing user enrollment, can be used to trigger this vulnerability. This vulnerability affects systems configured in routed firewall mode and in single or multiple context mode.
  
  Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
  
  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161019-asa-ca

Affected Products

• Vulnerable Cisco ASA Software running on the following products may be affected by this vulnerability:
  

  • Cisco ASA 5500 Series Adaptive Security Appliances
  • Cisco ASA 5500-X Series Next-Generation Firewalls
  • Cisco Adaptive Security Virtual Appliance (ASAv)
  • Cisco ASA for Firepower 9300 Series 
  • Cisco ASA for Firepower 4100 Series
  • Cisco ISA 3000 Industrial Security Appliance

  Refer to the "Fixed Software" section of this security advisory for more information about the affected releases.

  Vulnerable Products

  Cisco ASA Software is affected by this vulnerability if the local CA feature is configured. To verify whether the local CA is configured, use the show crypto ca server command and verify that the output shows the local CA state enabled.
  
  The following example shows a Cisco ASA with the local CA enabled:

  ciscoasa# show crypto ca server 
  
  Certificate Server LOCAL-CA-SERVER:
      Status: enabled
      State: enabled
      [...] 

  Note: Local CA feature is not enabled by default.
  
  

  Determining the Running Software Version

  To determine whether a vulnerable version of Cisco ASA Software is running on an appliance, administrators can use the show version command. The following example shows the results of the show version command on an appliance running Cisco ASA Software version 9.2(1):

  ciscoasa# show version | include Version
  Cisco Adaptive Security Appliance Software Version 9.2(1) 
  Device Manager Version 7.4(1)

  
  Customers who use Cisco Adaptive Security Device Manager (ASDM) to manage devices can locate the software version in the table that appears in the login window or the upper-left corner of the Cisco ASDM window.

  Products Confirmed Not Vulnerable

  Cisco Firepower Threat Defense software is not affected by this vulnerability.
  
  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 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.
  
  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 Technical Assistance Center (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.
  
  In the following table, the left column lists major releases of Cisco ASA Software. The right column indicates whether a major release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability.
  
  

  Cisco ASA Major Release	First Fixed Release
  7.21	Not Affected
  8.01	Affected; migrate to 9.1(7.7) or later
  8.11	Affected; migrate to 9.1(7.7) or later
  8.21	Affected; migrate to 9.1(7.7) or later
  8.31	Affected; migrate to 9.1(7.7) or later
  8.41	Affected; migrate to 9.1(7.7) or later
  8.51	Not Affected
  8.61	Affected; migrate to 9.1(7.7) or later
  8.71	Not Affected
  9.0	9.0(4.42) or later
  9.1	9.1(7.7) or later
  9.2	9.2(4.13) or later
  9.3	9.3(3.11) or later
  9.4	9.4(3.6) or later
  9.5	9.5(3) or later
  9.6	9.6(1.5) or later

  
  
  ¹Cisco ASA Software releases 7.2, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, and 8.7 have reached End of Software Maintenance. Customers should migrate to a supported release.

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 discovered during the resolution of support cases.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161019-asa-ca

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2016-October-19

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