Summary

• A vulnerability in the Internet Key Exchange Version 2 (IKEv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device.

  This vulnerability is due to improper control of a resource. An attacker with the ability to spoof a trusted IKEv2 site-to-site VPN peer and in possession of valid IKEv2 credentials for that peer could exploit this vulnerability by sending malformed, authenticated IKEv2 messages to an affected device. A successful exploit could allow the attacker to trigger a reload of the device.

  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-asaftd-ikev2-dos-g4cmrr7C

  This advisory is part of the October 2021 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication. For a complete list of the advisories and links to them, see Cisco Event Response: October 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco products if they were running a vulnerable release of Cisco ASA Software or Cisco FTD Software and were configured with at least one IKEv2 site-to-site VPN peer.

  For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  Determine the IKEv2 Site-to-Site VPN Configuration

  To determine whether an IKEv2 site-to-site VPN peer is configured and enabled on the device, use the show running-config crypto CLI command and look for the presence of all of the following:

  • IKEv2 enabled on an interface
  • A crypto map specifying an IKEv2 proposal
  • The same crypto map in the same sequence number identifying a peer for the IPsec connection
  • The same crypto map enabled on an interface on which IKEv2 is enabled

  The following example shows the output of the show running-config crypto command on a device that has IKEv2 enabled on the outside interface on which crypto map abcmap in sequence number 1 specifies IKEv2 proposal secure and IPsec peer 10.10.4.108 and on which crypto map abcmap is bound to the outside interface:

  firewall# show running-config crypto
  .
  .
  .
  crypto ikev2 enable outside
  .
  .
  .
  crypto map abcmap 1 set peer 10.10.4.108
  crypto map abcmap 1 set ikev2 ipsec-proposal secure
  crypto map abcmap interface outside
  .
  .
  .
  firewall#

  In this example, the device is vulnerable to authenticated IKEv2 messages with an IPv4 source address of 10.10.4.108 destined to the outside interface.

  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 Cisco Firepower Management Center (FMC) Software.

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories 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.

  Fixed Releases

  At the time of publication, the release information in the following table(s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability described in this advisory and which release included the fix for this vulnerability.

  Cisco ASA Software

  Cisco has released the following software updates to address this vulnerability. Customers who require software updates for platforms or releases that are not listed are advised to contact their support organization.

  ASA Software Release	First Fixed Release for This Vulnerability
  9.7 and earlier1	Not vulnerable.
  9.8	9.8.4.40
  9.91	Migrate to a fixed release.
  9.101	Migrate to a fixed release.
  9.12	9.12.4.30
  9.131	Migrate to a fixed release.
  9.14	9.14.3.9
  9.15	9.15.1.17
  9.16	9.16.2

  1. Cisco ASA Software releases 9.7 and earlier as well as releases 9.9, 9.10, and 9.13 have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  Cisco FTD Software

  FTD Software Release	First Fixed Release for This Vulnerability
  6.2.2 and earlier1	Migrate to a fixed release.
  6.2.3	Migrate to a fixed release.
  6.3.01	Migrate to a fixed release.
  6.4.0	6.4.0.13 (Nov 2021)
  6.5.01	Migrate to a fixed release.
  6.6.0	6.6.5
  6.7.0	6.7.0.3 (Jan 2022)
  7.0.0	7.0.1

  1. Cisco FMC and FTD Software releases 6.2.2 and earlier, as well as releases 6.3.0 and 6.5.0, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

   

  For instructions on upgrading your FTD device, see Cisco Firepower Management Center Upgrade Guide.

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

• The Cisco 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 by Santosh Krishnamurthy of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ikev2-dos-g4cmrr7C

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the source section.	—	Final	2021-OCT-29
  1.0	Initial public release.	—	Final	2021-OCT-27

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