Summary

• A vulnerability in the software cryptography module of the Cisco Adaptive Security Virtual Appliance (ASAv) and Firepower 2100 Series running Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause an unexpected reload of the device that results in a denial of service (DoS) condition.

  The vulnerability is due to a logic error with how the software cryptography module handles IPsec sessions. An attacker could exploit this vulnerability by creating and sending traffic in a high number of IPsec sessions through the targeted device. A successful exploit could cause the device to reload and result in a DoS condition.

  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-20190501-asa-ipsec-dos

Affected Products

• Vulnerable Products

  This vulnerability affects only the Cisco Adaptive Security Virtual Appliance (ASAv) and Cisco Firepower 2100 Series running Cisco Adaptive Security Appliance (ASA) Software Release 9.9.2.18 and configured to support IPsec connections through the device.

  The device should be considered vulnerable if a crypto map is bound to an interface in the configuration. The administrator can issue the show running-config command and check for the crypto map <cryto_map_name> interface <interface_name> command.

  For information about which Cisco ASA Software releases are vulnerable, see the Fixed Software section of this advisory.

  Determining the Cisco ASA Software Release

  To determine which Cisco ASA Software release is running on a device, administrators can log in to the device, use the show version | include Version command in the CLI, and refer to the output of the command. The following example shows the output of the command for a device that is running Cisco ASA Software Release 9.9.2.18:

  ciscoasa# show version | include Version
  Cisco Adaptive Security Appliance Software Version 9.9.2.18
  Device Manager Version 7.4(1)
  .
  .
  .

  If a device is managed by using Cisco Adaptive Security Device Manager (ASDM), administrators can also determine which release is running on a device by referring to the release information in the table that appears in the Cisco ASDM login window or the Device Dashboard tab of the Cisco ASDM Home pane.

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
  
  Cisco has confirmed that this vulnerability does not affect the following Cisco products:

  • 3000 Series Industrial Security Appliances (ISA)
  • ASA 1000V Cloud Firewall
  • ASA 5500-X Series Firewalls
  • ASA 5500 Series Adaptive Security Appliances
  • ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
  • Firepower 4100 Series
  • Firepower 9300 Security Appliance
  • Firepower Threat Defense (FTD) Software
  • FTD Virtual (FTDv)

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: https://www.cisco.com/c/en/us/products/end-user-license-agreement.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:
  https://www.cisco.com/c/en/us/support/web/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

  Customers are advised to upgrade to an appropriate release as indicated in the applicable table in this section. To ensure a complete upgrade solution, customers should consider that this advisory is part of a collection that includes the following advisories:

  • cisco-sa-20190501-asa-csrf: Cisco Adaptive Security Appliance Software Cross-Site Request Forgery Vulnerability
  • cisco-sa-20190501-asa-frpwrtd-dos: Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software TCP Timer Handling Denial of Service Vulnerability
  • cisco-sa-20190501-asa-ftd-dos: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Denial of Service Vulnerability
  • cisco-sa-20190501-asa-ftd-entropy: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Low-Entropy Keys Vulnerability
  • cisco-sa-20190501-asa-ftd-ike-dos: Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software MOBIKE Denial of Service Vulnerability
  • cisco-sa-20190501-asaftd-saml-vpn: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software VPN SAML Authentication Bypass Vulnerability
  • cisco-sa-20190501-asa-ipsec-dos: Cisco Adaptive Security Appliance Software IPsec Denial of Service Vulnerability
  • cisco-sa-20190501-firepower-dos: Cisco Firepower Threat Defense Software TCP Ingress Handler Denial of Service Vulnerability
  • cisco-sa-20190501-frpwr-dos: Cisco Firepower Threat Defense Software Packet Processing Denial of Service Vulnerability
  • cisco-sa-20190501-frpwr-smb-snort: Cisco Firepower Threat Defense Software SMB Protocol Preprocessor Detection Engine Denial of Service Vulnerabilities
  • cisco-sa-20190501-sd-cpu-dos: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Denial of Service Vulnerability

  In the following table(s), the left column lists Cisco software releases. The center column indicates whether a release is affected by the vulnerability described in this advisory and the release that includes the fix for this vulnerability. The right column indicates whether a release is affected by all the vulnerabilities described in this collection of advisories and which release includes fixes for those vulnerabilities.

  Cisco ASA Software

  Cisco ASA Software Release	Recommended Release for This Vulnerability	Recommended Release for All Vulnerabilities Described in the Collection of Advisories
  Prior to 9.41	Not vulnerable	9.4.4.34
  9.4	Not vulnerable	9.4.4.34
  9.51	Not vulnerable	9.6.4.25
  9.6	Not vulnerable	9.6.4.25
  9.71	Not vulnerable	9.8.4
  9.8	Not vulnerable	9.8.4
  9.9	9.9.2.50	9.9.2.50
  9.10	Not vulnerable	9.10.1.17
  9.12	Not vulnerable	Not vulnerable

  ¹Cisco ASA Software releases prior to Release 9.4 and Cisco ASA Software Releases 9.5 and 9.7 have reached end of maintenance. Customers should migrate to a supported release that includes the fix for this 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 the resolution of a Cisco TAC support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190501-asa-ipsec-dos

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2019-May-01

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