Summary

• A vulnerability in the software cryptography module of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker or an unauthenticated attacker in a man-in-the-middle position 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 in how the software cryptography module handles specific types of decryption errors. An attacker could exploit this vulnerability by sending malicious packets over an established IPsec connection. A successful exploit could cause the device to crash, forcing it to reload. Important: Successful exploitation of this vulnerability would not cause a compromise of any encrypted data.

  Note: This vulnerability affects only Cisco ASA Software Release 9.16.1 and Cisco FTD Software Release 7.0.0.

  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-asa-ftd-ipsec-dos-TFKQbgWC

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running Cisco ASA Software Release 9.16.1 or Cisco FTD Software Release 7.0.0 and are configured to support IPsec connections to the device.

  • Firepower 2100 Series
  • Firepower NGFW Virtual
  • Adaptive Security Virtual Appliance (ASAv)

  Note: These devices are not vulnerable if Federal Information Processing Standards Publication (FIPS) mode is enabled.

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

  Determine the Device Configuration

  The device should be considered vulnerable if either of these configuration parameters exists on the device:

  1. If there is a crypto map bound to an interface in the configuration. The administrator can issue the show running-config command and check for the crypto map interface command.
     
     
  2. If there is a crypto IPsec profile bound to a tunnel interface in the configuration. The administrator can issue the show running-config command and check for the tunnel protection ipsec command.

  The device is considered not vulnerable if FIPS mode is enabled.

  1. For ASA Software, the administrator can issue the show running-config | include fips-enable command and if the output contains the fips-enable keyword the device is considered not vulnerable.
     
     
  2. In Cisco FTD Software, FIPS mode is enabled indirectly by configuring either Common Criteria (CC) mode or Unified Capabilities Approved Products List (UCAPL) mode. For further information on determining if FIPS is configured for Cisco FTD Software, see the Security Certifications Compliance chapter of the Firepower Management Center Configuration Guide.

  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 ASA Software and Cisco FTD Software running on any platform other than the platforms listed in the Vulnerable Products section.

  In addition, 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

• 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 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

  This vulnerability is fixed in Cisco ASA Software releases 9.16.1.28 and later.

  This vulnerability is fixed for Cisco Firepower 2100 Series by Cisco_FTD_SSP_FP2K_Patch-7.0.0.1-15.sh.REL.tar.

  This vulnerability is fixed for Cisco Firepower NGFW Virtual by Cisco_FTD_Patch-7.0.0.1-15.sh.REL.tar.

  Note: This vulnerability affects only Cisco ASA Software Release 9.16.1 and Cisco FTD Software Release 7.0.0.

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-asa-ftd-ipsec-dos-TFKQbgWC

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the first fixed release for the ASA platform.	Fixed Software	Final	2021-JUL-16
  1.0	Initial public release.	-	Final	2021-JUL-15

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