Summary

• A vulnerability in the IPsec code of Cisco ASA Software could allow an authenticated, remote attacker to cause a reload of the affected system.
  
  The vulnerability is due to improper parsing of malformed IPsec packets. An attacker could exploit this vulnerability by sending malformed IPsec packets to the affected system.
  
  Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed firewall mode only and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. An attacker needs to establish a valid IPsec tunnel before exploiting this vulnerability.
  
  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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170419-asa-ipsec

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco ASA Software running on the following products:
  

  • Cisco ASA 1000V Cloud Firewall
  • Cisco ASA 5500 Series Adaptive Security Appliances
  • Cisco ASA 5500-X Series Next-Generation Firewalls
  • Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
  • Cisco Adaptive Security Virtual Appliance (ASAv)
  • Cisco Firepower 9300 ASA Security Module
  • Cisco ISA 3000 Industrial Security Appliance

  
  Refer to the “Fixed Software” section of this security advisory for more information about affected releases.
  
  Cisco ASA Software is affected by this vulnerability if the system is configured to terminate IPsec VPN connections. This includes the following:
  

  • LAN-to-LAN IPsec VPN
  • Remote access VPN using the IPsec VPN client
  • Layer 2 Tunneling Protocol (L2TP)-over-IPsec VPN connections
  • Internet Key Exchange Version 2 (IKEv2) AnyConnect

  Cisco ASA Software is not affected by this vulnerability if the system is configured to terminate only the following VPN connections:
  

  • Clientless SSL
  • AnyConnect SSL

  To determine whether an appliance running Cisco ASA Software is configured to terminate IPsec VPN connections, a crypto map must be configured for at least one interface. Administrators should use the show running-config crypto map | include interface command and verify that it returns output. The following example shows a crypto map named outside_map configured on the outside interface:
  

  ciscoasa# show running-config crypto map | include interface
  
  crypto map outside_map interface outside

  Note: IPsec VPN is not configured by default.
  
  Determining the Running Software Release
  
  To determine whether a vulnerable release 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 Release 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 release in the table that appears in the login window or the upper-left corner of the Cisco ASDM window.

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.
  
  Cisco has confirmed that this vulnerability does not affect Cisco Firepower Threat Defense Software.

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 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

  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 Software Major Release	First Fixed Release
  Prior to 9.01	Affected, migrate to 9.1(7.8) or later
  9.01	Affected, migrate to 9.1(7.8) or later
  9.1	9.1(7.8) or later
  9.2	9.2(4.15) or later
  9.31	Affected, migrate to 9.4(4) or later
  9.4	9.4(4) or later
  9.5	9.5(3.2) or later
  9.6	9.6(2) or later
  9.7	Not affected
  9.8	Not affected

  
  ¹ Cisco ASA Software releases prior to 9.1 and Cisco ASA Software Release 9.3 have reached end-of-software maintenance. Customers should migrate to a supported release.
  
  Note: It is possible that certain fixed software releases for this vulnerability are affected by a bug described in Cisco Field Notice FN-64291 where a security appliance may fail to pass traffic after 213 days of uptime. Customers should review this notice before determining a course of action for addressing the vulnerability described in this advisory. The issue described in the Cisco Field Notice is not a security vulnerability.

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 internal testing.

URL

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170419-asa-ipsec

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2017-April-19

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