Summary

• A vulnerability in the implementation of Security Assertion Markup Language (SAML) 2.0 Single Sign-On (SSO) for Clientless SSL VPN (WebVPN) and AnyConnect Remote Access VPN in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to successfully establish a VPN session to an affected device.
  
  The vulnerability is due to improper credential management when using NT LAN Manager (NTLM) or basic authentication. An attacker could exploit this vulnerability by opening a VPN session to an affected device after another VPN user has successfully authenticated to the affected device via SAML SSO. A successful exploit could allow the attacker to connect to secured networks behind 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-20190501-asaftd-saml-vpn

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products that are running Cisco ASA Software Release 9.7.1 or later or Cisco FTD Software Release 6.2.1 or later configured for SAML 2.0-based SSO for Clientless SSL VPN (WebVPN) or AnyConnect Remote Access VPN:

  • 3000 Series Industrial Security Appliances (ISAs)
  • Adaptive Security Appliance (ASA) 5500-X Series Firewalls
  • ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
  • Adaptive Security Virtual Appliance (ASAv)
  • Firepower 2100 Series
  • Firepower 4100 Series
  • Firepower 9300 Security Appliances
  • Firepower Threat Defense Virtual

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

  ASA and FTD Features

  Cisco ASA Software and FTD Software are vulnerable only if all of the following features are configured:

  1. SAML 2.0 Identity Provider (IdP)
  2. SAML 2.0 Service Provider (SP)
  3. AnyConnect Remote Access VPN or Clientless SSL VPN (WebVPN)

  Note: SAML 2.0 for AnyConnect features are first supported as of ASA Release 9.7.1, FTD Release 6.2.1, and AnyConnect Secure Mobility Client Release 4.4.00243.

  To determine whether ASA or FTD is configured with a SAML 2.0 IdP, administrators can use the show webvpn saml idp CLI command. The following output shows an ASA configured with a SAML 2.0 IdP:

  ciscoasa# show webvpn saml idp
   saml idp my_domain_idp
    url sign-in https://asa-dev.my.domain.com/idp/endpoint/HttpRedirect
    url sign-out https://asa-dev.my.domain.com/idp/endpoint/HttpRedirect
    trustpoint idp my_domain_trustpoint
    trustpoint sp asa_trustpoint

  To determine whether ASA or FTD is configured with SAML 2.0 SP, administrators can use the show running-config tunnel-group | include remote-access|webvpn-attributes|saml CLI command. The following output shows an ASA configured with SAML 2.0 SP:

  ciscoasa# show running-config tunnel-group | include remote-access|webvpn-attributes|saml
  tunnel-group cloud_idp_onelogin type remote-access
  tunnel-group cloud_idp_onelogin webvpn-attributes
   authentication saml
   saml identity-provider my_domain_idp

  To determine whether ASA or FTD is configured for AnyConnect Remote Access VPN or Clientless SSL VPN (WebVPN), administrators can use the show running-config CLI command and consult the following table for vulnerable configurations:

  Feature	Vulnerable Configuration
  AnyConnect IKEv2 Remote Access (with client services)	crypto ikev2 enable <interface_name> client-services port <port #> webvpn  anyconnect enable
  AnyConnect IKEv2 Remote Access (without client services)	crypto ikev2 enable <interface_name> webvpn  anyconnect enable
  AnyConnect SSL VPN	webvpn  enable <interface_name>
  Clientless SSL VPN (WebVPN)	webvpn  enable <interface_name>

  Determining the Cisco ASA Software Release

  To determine which Cisco ASA Software release is running on a device, administrators can log in to the device, use the show version | include Version command in the CLI, and refer to the output of the command. The following example shows the output of the command for a device that is running Cisco ASA Software Release 9.9.2.18:

  ciscoasa# show version | include Version
  Cisco Adaptive Security Appliance Software Version 9.9.2.18
  Device Manager Version 7.4(1)
  .
  .
  .

  If a device is managed by using Cisco Adaptive Security Device Manager (ASDM), administrators can also determine which release is running on a device by referring to the release information in the table that appears in the Cisco ASDM login window or the Device Dashboard tab of the Cisco ASDM Home pane.

  Determining the Cisco FTD Software Release

  To determine which Cisco FTD Software release is running on a device, administrators can log in to the device, use the show version command in the CLI, and refer to the output of the command. The following example shows the output of the command for a device that is running Cisco FTD Software Release 6.2.0:

  > show version
  
  ---------------------[ ftd ]---------------------
  Model : Cisco ASA5525-X Threat Defense (75) Version 6.2.0 (Build 362)
  UUID : 2849ba3c-ecb8-11e6-98ca-b9fc2975893c
  Rules update version : 2017-03-15-001-vrt
  VDB version : 279
  ----------------------------------------------------

  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 or FTD Software running on the following platforms:

  • ASA 1000V Cloud Firewall
  • ASA 5505 Adaptive Security Appliance¹

  ¹ ASA 5500 Series Adaptive Security Appliances other than the ASA 5505 have reached the end-of-support milestone and are no longer evaluated for security vulnerabilities.

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. To ensure a complete upgrade solution, customers should consider that this advisory is part of a collection that includes the following advisories:

  • cisco-sa-20190501-asa-csrf: Cisco Adaptive Security Appliance Software Cross-Site Request Forgery Vulnerability
  • cisco-sa-20190501-asa-frpwrtd-dos: Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software TCP Timer Handling Denial of Service Vulnerability
  • cisco-sa-20190501-asa-ftd-dos: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Denial of Service Vulnerability
  • cisco-sa-20190501-asa-ftd-entropy: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Low-Entropy Keys Vulnerability
  • cisco-sa-20190501-asa-ftd-ike-dos: Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software MOBIKE Denial of Service Vulnerability
  • cisco-sa-20190501-asaftd-saml-vpn: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software VPN SAML Authentication Bypass Vulnerability
  • cisco-sa-20190501-asa-ipsec-dos: Cisco Adaptive Security Appliance Software IPsec Denial of Service Vulnerability
  • cisco-sa-20190501-firepower-dos: Cisco Firepower Threat Defense Software TCP Ingress Handler Denial of Service Vulnerability
  • cisco-sa-20190501-frpwr-dos: Cisco Firepower Threat Defense Software Packet Processing Denial of Service Vulnerability
  • cisco-sa-20190501-frpwr-smb-snort: Cisco Firepower Threat Defense Software SMB Protocol Preprocessor Detection Engine Denial of Service Vulnerabilities
  • cisco-sa-20190501-sd-cpu-dos: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Denial of Service Vulnerability

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

  Cisco ASA Software

  Cisco ASA Software Release	Recommended Release for This Vulnerability	Recommended Release for All Vulnerabilities Described in the Collection of Advisories
  Prior to 9.41	Not vulnerable	9.4.4.34
  9.4	Not vulnerable	9.4.4.34
  9.51	Not vulnerable	9.6.4.25
  9.6	Not vulnerable	9.6.4.25
  9.71	9.8.4	9.8.4
  9.8	9.8.4	9.8.4
  9.9	9.9.2.50	9.9.2.50
  9.10	9.10.1.17	9.10.1.17
  9.12	Not vulnerable	Not vulnerable

  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	Recommended Release for This Vulnerability	Recommended Release for All Vulnerabilities Described in the Collection of Advisories
  6.0	Not vulnerable	6.2.3.12
  6.0.1	Not vulnerable	6.2.3.12
  6.1.0	Not vulnerable	6.2.3.12
  6.2.0	Not vulnerable	6.2.3.12
  6.2.1	6.2.3.12	6.2.3.12
  6.2.2	6.2.3.12	6.2.3.12
  6.2.3	6.2.3.12	6.2.3.12
  6.3.0	6.3.0.3	6.3.0.3
  6.4.0	Not vulnerable	Not vulnerable

  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-20190501-asaftd-saml-vpn

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the FTD fixed releases table to indicate that FTD Software Release 6.3.0.3 is available.	Fixed Software	Final	2019-May-02
  1.0	Initial public release.	—	Final	2019-May-01

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