Summary

• A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and obtain read and delete access to sensitive files on a targeted system.

  The vulnerability is due to a lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences. An exploit could allow the attacker to view or delete arbitrary files on the targeted system. When the device is reloaded after exploitation of this vulnerability, any files that were deleted are restored.

  The attacker can only view and delete files within the web services file system. This file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability can not be used to obtain access to ASA or FTD system files or underlying operating system (OS) files. Reloading the affected device will restore all files within the web services file system.

  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-path-JE3azWw43

  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 products if they are running a vulnerable release of Cisco ASA Software or FTD Software with a vulnerable AnyConnect or WebVPN configuration.

  ASA Software

  In the following table, the left column lists the Cisco ASA features that are vulnerable. The right column indicates the basic configuration for the feature from the show running-config CLI command. If the device is configured for one of these features, it is vulnerable.

  Cisco ASA Feature	Vulnerable Configuration
  AnyConnect IKEv2 Remote Access (with client services)	crypto ikev2 enable <interface_name> client-services port <port #>
  AnyConnect SSL VPN	webvpn    enable <interface_name>
  Clientless SSL VPN	webvpn    enable <interface_name>

  FTD Software

  In the following table, the left column lists the Cisco FTD features that are vulnerable. The right column indicates the basic configuration for the feature from the show running-config CLI command. If the device is configured for one of these features, it is vulnerable.

  Cisco FTD Feature	Vulnerable Configuration
  AnyConnect IKEv2 Remote Access (with client services)1,2	crypto ikev2 enable <interface_name> client-services port <port #>
  AnyConnect SSL VPN1,2	webvpn   enable <interface_name>

  1. Remote Access VPN features are enabled via Devices > VPN > Remote Access in the Cisco FMC or via Device > Remote Access VPN in Cisco Firepower Device Manager (FDM).
  2. Remote Access VPN features are first supported as of Cisco FTD Software Release 6.2.2.

  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.

Details

• The attacker can view and delete files within the web services file system only. The web services file system is enabled for the WebVPN and AnyConnect features outlined in the Vulnerable Products section of this advisory; therefore, this vulnerability does not apply to the ASA and FTD system files or underlying operating system (OS) files. The Web Services files that the attacker can view may have information such as WebVPN configuration, bookmarks, web cookies, partial web content, and HTTP URLs.

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 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 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 9.51	Migrate to a fixed release.	Migrate to a fixed release.
  9.6	9.6.4.40	Migrate to a fixed release.
  9.71	Migrate to a fixed release.	Migrate to a fixed release.
  9.8	9.8.4.15	9.8.4.20
  9.9	9.9.2.66	9.9.2.67
  9.10	9.10.1.37	9.10.1.40
  9.12	9.12.3.2	9.12.3.9
  9.13	9.13.1.7	9.13.1.10
  9.14	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.

  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 6.2.31	Migrate to a fixed release.	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	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	6.3.0.6 (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	6.4.0.8	6.4.0.9
  6.5.0	6.5.0.4	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

• Cisco would like to thank Mikhail Klyuchnikov of Positive Technologies for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-path-JE3azWw43

Revision History

• Version	Description	Section	Status	Date
  1.2	Updated Hot Fixes for FTD releases 6.4.0 and 6.5.0.	Fixed Releases	Final	2020-MAY-15
  1.3	Updated fixed release information for FTD Release 6.4.0.	Fixed Releases	Final	2020-MAY-06
  1.1	Updated ASA Fixed Release table to indicate 9.10.1.40 as the correct fixed release instead of 9.10.1.39.	Fixed Releases	Final	2020-MAY-06
  1.0	Initial public release.	—	Final	2020-MAY-06

  Show Less

---