Summary

• A vulnerability in the FTP inspection engine of Cisco Adaptive Security (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

  The vulnerability is due to insufficient validation of FTP data. An attacker could exploit this vulnerability by sending malicious FTP traffic through an affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected 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-20191002-asa-dos

  This advisory is part of the October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 10 Cisco Security Advisories that describe 18 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco products if they are running a vulnerable release of Cisco ASA Software or Cisco FTD Software that is configured to perform FTP inspection.

  FTP inspection is enabled by default in Cisco FTD Software. For detailed information about the default settings for application inspection policies, see the Cisco ASA Series Firewall CLI Configuration Guide.

  Determine Whether FTP Inspection Is Enabled on an ASA

  To determine whether FTP inspection is enabled on an ASA, administrators can use the show running-config policy-map command and then the show running-config service-policy command.

  First use the show running-config policy-map command, and check whether the inspect ftp command is present in at least one policy map. In the following output, the global-policy policy map includes the inspect ftp command:

  asa# show running-config policy-map 
  !
  policy-map global_policy
   class inspection_default
    inspect ip-options 
    inspect netbios 
    inspect rtsp 
    inspect sunrpc 
    inspect tftp 
    inspect xdmcp 
    inspect dns preset_dns_map 
    inspect ftp 
    inspect h323 h225

  Next use the show running-config service-policy command, and check whether the policy map is applied, either globally or to a single interface. The following output shows the global-policy policy map applied globally:

  asa# show running-config service-policy
  service-policy global_policy global

  If the policy map that contains the inspect ftp command is applied globally or to an interface, FTP inspection is enabled.

  Determine Whether FTP Inspection Is Enabled on FTD

  To determine whether FTP inspection is enabled on FTD, administrators can do one of the following:

  • For devices that are managed by using Cisco Firepower Management Center (FMC), open Cisco FMC, choose Policies > Access Control > Malware & File, and then choose an access control rule. Click the File Policy tab to view detailed information about file policies that are associated with the rule.
  • For devices that are managed by using Cisco Firepower Device Manager (FDM), open Cisco FDM, choose Policies > Access Control, and then choose an access control rule. Click the File Policy tab to view detailed information about file policies that are associated with the rule. Note that Cisco FDM supports predefined file policies only; administrators cannot create file policies for access control rules.

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

  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 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 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 tables, the left column lists releases of Cisco ASA Software, Cisco FMC Software, or Cisco FTD Software. 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 ASA Software

  Cisco ASA Software Release	First Fixed Release for This Vulnerability	First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
  Earlier than 9.41	Migrate to a fixed release.	Migrate to a fixed release.
  9.41	Migrate to a fixed release.	Migrate to a fixed release.
  9.51	Migrate to a fixed release.	Migrate to a fixed release.
  9.6	9.6.4.34	9.6.4.34
  9.71	Migrate to a fixed release.	Migrate to a fixed release.
  9.8	9.8.4.10	9.8.4.10
  9.9	9.9.2.56	Migrate to a fixed release.
  9.10	9.10.1.30	9.10.1.30
  9.12	9.12.2.52	9.12.2.5
  9.13	Not vulnerable.	Not vulnerable.

  1. Cisco ASA Software releases 9.5 and earlier, as well as Release 9.7, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  2. This vulnerability was first addressed in release 9.12.2.4. Release 9.12.2.4 was deferred and removed from CCO. Customers running release 9.12.2.4 are not affected by this vulnerability. Customers running on a Firepower 2100 Series Appliance should consider upgrading to a non-deferred release.

  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	Migrate to a fixed release.	Migrate to a fixed release.
  6.1.0	Migrate to a fixed release.	Migrate to a fixed release.
  6.2.0	Migrate to a fixed release.	Migrate to a fixed release.
  6.2.1	Migrate to a fixed release.	Migrate to a fixed release.
  6.2.2	Migrate to a fixed release.	Migrate to a fixed release.
  6.2.3	6.2.3.15	Migrate to a fixed release.
  6.3.0	6.3.0.5 (late October 2019)	6.4.0.4
  6.4.0	6.4.0.4	6.4.0.4
  6.5.0	Not vulnerable.	Not vulnerable.

  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 internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191002-asa-dos

Revision History

• Version	Description	Section	Status	Date
  1.2	Updated ASA Fixed Release table.	Fixed Software	Final	2019-November-14
  1.1	Updated FTD Fixed Release table.	Fixed Software	Final	2019-October-18
  1.0	Initial public release.	—	Final	2019-October-02

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