Summary

• A vulnerability in the cryptographic driver for Cisco Adaptive Security Appliance Software (ASA) and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reboot unexpectedly.

  The vulnerability is due to incomplete input validation of a Secure Sockets Layer (SSL) or Transport Layer Security (TLS) ingress packet header. An attacker could exploit this vulnerability by sending a crafted TLS/SSL packet to an interface on the targeted device. An exploit could allow the attacker to cause the device to reload, which will result in a denial of service (DoS) condition.

  Note: Only traffic directed to the affected system can be used to exploit this vulnerability. This vulnerability affects systems configured in routed and transparent firewall mode and in single or multiple context mode. This vulnerability can be triggered by IPv4 and IPv6 traffic. A valid SSL or TLS session is required to exploit 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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190710-asa-ftd-dos

Affected Products

• 
  

  Vulnerable Products

  This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco ASA Software or FTD Software:

  • ASA 5506-X
  • ASA 5506-X with FirePOWER Services
  • ASA 5506H-X
  • ASA 5506H-X with FirePOWER Services
  • ASA 5506W-X
  • ASA 5506W-X with FirePOWER Services
  • ASA 5508-X
  • ASA 5508-X with FirePOWER Services
  • ASA 5516-X
  • ASA 5516-X with FirePOWER Services

  This vulnerability applies only to the ASA hardware platforms that use a specific cryptographic driver for SSL and TLS packet decryption and encryption. There are multiple features that, when enabled, cause Cisco ASA Software or FTD Software to process SSL/TLS packets. These features include, but are not limited to, the following:

  • AnyConnect and Clientless SSL VPN
  • HTTP server used for the management interface

  To verify whether a device running Cisco ASA Software or FTD Software could process SSL or TLS packets, use the show asp table socket | include SSL|DTLS command and verify that it returns output. When this command returns any output, the device is vulnerable. When this command returns empty output, the device is not vulnerable. The following example shows the output of the show asp table socket | include SSL|DTLS command from a device that is vulnerable:

  BSNS-ASA5505-4# show asp table socket | include SSL|DTLS
  SSL       0005aa68  LISTEN     x.x.x.x:443      0.0.0.0:*   
  SSL       002d9e38  LISTEN     x.x.x.x:8443     0.0.0.0:*
  DTLS      0018f7a8  LISTEN     10.0.0.250:443   0.0.0.0:*  

  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 (ISAs)
  • 7600 Series ASA Services Module
  • Adaptive Security Virtual Appliance (ASAv)
  • ASA 1000V Cloud Firewall
  • ASA 5505 Adaptive Security Appliance
  • ASA 5510 Adaptive Security Appliance
  • ASA 5512-X Adaptive Security Appliance
  • ASA 5515-X Adaptive Security Appliance
  • ASA 5520 Adaptive Security Appliance
  • ASA 5525-X Adaptive Security Appliance
  • ASA 5540 Adaptive Security Appliance
  • ASA 5545-X Adaptive Security Appliance
  • ASA 5550 Adaptive Security Appliance
  • ASA 5555-X Adaptive Security Appliance
  • ASA 5580 Adaptive Security Appliance
  • ASA 5585-X Adaptive Security Appliance
  • ASA 5512-X with FirePOWER Services
  • ASA 5515-X with FirePOWER Services
  • ASA 5525-X with FirePOWER Services
  • ASA 5545-X with FirePOWER Services
  • ASA 5555-X with FirePOWER Services
  • ASA 5585-X with FirePOWER SSP-10, SSP-20, SSP-40, or SSP-60
  • Catalyst 6500 Series ASA Services Module
  • Firepower 2100 Series
  • Firepower 4100 Series
  • FirePOWER 7000 Series Appliances
  • FirePOWER 8000 Series Appliances
  • Firepower 9300 Security Appliances
  • Firepower Threat Defense Virtual (FTDv)
  • Industrial Security Appliance 3000

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. In the following table(s), the left column lists Cisco software releases and the right column indicates whether a release is affected by the vulnerability described in this advisory and the release that includes the fix for this vulnerability

  Cisco ASA Software

  Cisco ASA Software Release	First Fixed Release for This Vulnerability
  Prior to 9.41	9.4.4.36
  9.4	9.4.4.36
  9.51	9.6.4.29
  9.6	9.6.4.29
  9.71	9.8.4.3
  9.8	9.8.4.3
  9.9	9.9.2.52
  9.10	9.10.1.22
  9.12	9.12.2

  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.

  Cisco FTD Software

  Cisco FTD Software Release	First Fixed Release for This Vulnerability
  6.01	6.2.3.13
  6.0.11	6.2.3.13
  6.1.0	6.2.3.13
  6.2.0	6.2.3.13
  6.2.1	6.2.3.13
  6.2.2	6.2.3.13
  6.2.3	6.2.3.13
  6.3.0	Cisco_FTD_Hotfix_AA-6.3.0.4-2 or 6.3.0.4 (August 2019)
  6.4.0	6.4.0.2

  ¹Cisco FTD Software releases prior to and including Release 6.0.1 have reached end of maintenance. Customers should 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-20190710-asa-ftd-dos

Revision History

• Version	Description	Section	Status	Date
  1.1	Added the hotfix information for the FTD 6.3.0 release.	Fixed Software	Final	2019-July-11
  1.0	Initial public release.	—	Final	2019-July-10

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