Summary

• A vulnerability in the VPN System Logging functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a memory leak that can deplete system memory over time, which can cause unexpected system behaviors or device crashes.

  The vulnerability is due to the system memory not being properly freed for a VPN System Logging event generated when a VPN session is created or deleted. An attacker could exploit this vulnerability by repeatedly creating or deleting a VPN tunnel connection, which could leak a small amount of system memory for each logging event. A successful exploit could allow the attacker to cause system memory depletion, which can lead to a systemwide denial of service (DoS) condition. The attacker does not have any control of whether VPN System Logging is configured or not on the device, but it is enabled by default.

  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-ftd-dos-Rdpe34sd8

  This advisory is part of the May 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 12 Cisco Security Advisories that describe 12 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: May 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco FTD Software releases 6.2.3.12, 6.2.3.13, 6.2.3.14, and 6.2.3.15 if VPN System Logging is configured.

  Determining if VPN System Logging Is Configured

  The administrator can check if VPN System Logging is configured on the Firepower Management Center (FMC) by clicking the System Status icon and navigating to VPN Logging Settings under Platform Settings > Syslog > Logging Setup.

  Please refer to VPN System Logs for additional information.

  Note: VPN System Logging is automatically enabled to be sent to the FMC by default whenever a device is configured with site-to-site or remote access VPNs.

  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 Adaptive Security Appliance (ASA) Software or Cisco Firepower Management Center (FMC).

Workarounds

• Disabling the VPN System Logging feature eliminates the attack vector for this vulnerability and may be a suitable mitigation until affected devices can be upgraded. Administrator can disable VPN System Logging on the Firepower Management Center (FMC) by clicking the System Status icon and navigating to VPN Logging Settings under Platform Settings > Syslog > Logging Setup.

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

  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 first release that includes the fix for this vulnerability. The right column indicates whether a release is affected by any of the vulnerabilities described in this bundle and which release includes fixes for those vulnerabilities.

  Cisco FTD Software

  Cisco FTD Software Release	First Fixed Release for This Vulnerability	First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
  Earlier than 6.1.01	Not vulnerable.	Migrate to a fixed release.
  6.1.0	Not vulnerable.	Migrate to a fixed release.
  6.2.0	Not vulnerable.	Migrate to a fixed release.
  6.2.1	Not vulnerable.	Migrate to a fixed release.
  6.2.2	Not vulnerable.	Migrate to a fixed release.
  6.2.3	6.2.3.16 (June 2020) Cisco_FTD_Hotfix_DT-6.2.3.16-3.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_DT-6.2.3.16-3.sh.REL.tar Cisco_FTD_SSP_Hotfix_DT-6.2.3.16-3.sh.REL.tar	6.2.3.16 (June 2020) Cisco_FTD_Hotfix_DT-6.2.3.16-3.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_DT-6.2.3.16-3.sh.REL.tar Cisco_FTD_SSP_Hotfix_DT-6.2.3.16-3.sh.REL.tar
  6.3.0	Not vulnerable.	6.3.0.6 (future release) Cisco_FTD_Hotfix_AO-6.3.0.6-2.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_ AO-6.3.0.6-2.sh.REL.tar Cisco_FTD_SSP_Hotfix_ AO-6.3.0.6-2.sh.REL.tar
  6.4.0	Not vulnerable.	6.4.0.9
  6.5.0	Not vulnerable.	6.5.0.5 (future release) Cisco_FTD_Hotfix_H-6.5.0.5-2.sh.REL.tar and later Cisco_FTD_SSP_FP1K_Hotfix_H-6.5.0.5-2.sh.REL.tar and later Cisco_FTD_SSP_FP2K_Hotfix_H-6.5.0.5-2.sh.REL.tar and later Cisco_FTD_SSP_Hotfix_H-6.5.0.5-2.sh.REL.tar and later
  6.6.0	Not vulnerable.	6.6.0

  1. Cisco FMC and FTD Software releases 6.0.1 and earlier have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  To upgrade to a fixed release of Cisco FTD Software, customers can do one of the following:

  • For devices that are managed by using Cisco Firepower Management Center (FMC), use the FMC interface to install the upgrade. After installation is complete, reapply the access control policy.
  • For devices that are managed by using Cisco Firepower Device Manager (FDM), use the FDM interface to install the upgrade. After installation is complete, reapply the access control policy.

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-ftd-dos-Rdpe34sd8

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated Hot Fixes for FTD releases 6.4.0 and 6.5.0.	Fixed Releases	Final	2020-MAY-15
  1.2	Updated fixed release information for FTD Release 6.4.0.	Fixed Releases	Final	2020-MAY-06
  1.0	Initial public release.	—	Final	2020-MAY-06

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