Summary

• A vulnerability in the Traversal Using Relay NAT (TURN) server included with Cisco Meeting Server (CMS) could allow an authenticated, remote attacker to gain unauthenticated or unauthorized access to components of or sensitive information in an affected system.
  
  The vulnerability is due to an incorrect default configuration of the TURN server, which could expose internal interfaces and ports on the external interface of an affected system. An attacker could exploit this vulnerability by using a TURN server to perform an unauthorized connection to a Call Bridge, a Web Bridge, or a database cluster in an affected system, depending on the deployment model and CMS services in use. A successful exploit could allow the attacker to gain unauthenticated access to a Call Bridge or database cluster in an affected system or gain unauthorized access to sensitive meeting information in an affected system. To exploit this vulnerability, the attacker must have valid credentials for the TURN server of the affected 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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170913-cmsturn

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Meeting Server (CMS) deployments that are running a CMS Software release prior to Release 2.0.16, 2.1.11, or 2.2.6, if the deployment meets all the following additional criteria:

  • The deployment uses the TURN server included with CMS.
  • The TURN server uses Transport Layer Security (TLS) connections; on the Mainboard Management Processor (MMP) interface, the TLS protocol is configured to run with the TURN server.
  • The TURN server is running on the same virtual machine as other colocated CMS services.
  • The TURN server is running on the same virtual machine as a Call Bridge, a Web Bridge, or a database node that is part of a database cluster in the CMS deployment.

  Administrators can determine which CMS Software release is running on a device by using the version command in the CLI. The following example shows the output of the command for a device that is running CMS Software Release 2.0.6:

  system> version
  
  2_0_6

  For TLS to be configured to run with a TURN server, the turn tls and turn certs commands must be present in the configuration. To check the MMP TLS configuration for the TURN server, administrators can issue the turn command in the MMP console.

  The following example shows the output of the turn command for a system that does not have TLS configured for the TURN server:

  cms> turn
  
  Enabled       : true
  Username      : cisco
  Password      : 1234
  Realm         : nicedet.com
  Public IP     : none
  Relay address : 1.2.3.4
  Listen interface a

  The following example shows the output of the turn command for a system that has TLS configured for the TURN server:

  cms> turn
  
  Enabled       : true
  Username      : cisco
  Password      : 1234
  Realm         : nicedet.com
  Public IP     : none
  Relay address : 1.2.3.4
  TLS port               : 3479
  TLS cert               : turn.crt
  TLS key       : turn.key
  TLS bundle    : none
  Listen interface a

  
  

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.

  Cisco has confirmed that this vulnerability does not affect CMS deployments that meet any of the following conditions:

  • The deployment does not use a TURN server.
  • The deployment uses a third-party TURN server.
  • The TURN server is running on a dedicated CMS with no other colocated services.
  • The TLS configuration is disabled for the TURN server.

Details

• Cisco Meeting Server (CMS) incorporates video, audio, and content-sharing capabilities into software that can be accessed via a conference room, desktop, or mobile device. CMS works across Cisco video rooms and connects with Skype for Business and other hardware providers to allow a seamless meeting architecture. This capability exists via collaboration between Cisco and Acano, who joined Cisco in early 2016.

  The TURN server included with CMS contains a vulnerability that could allow an authenticated, remote attacker to gain unauthorized access to components of or sensitive information in an affected system, depending on the deployment model and CMS services in use. The vulnerability is due to an incorrect default configuration of the TURN server, which could expose internal interfaces and ports on the external interface of an affected system.

  If the TURN server is running on the same virtual machine (colocated) as a CMS Call Bridge, the attacker could gain unauthenticated access to the Web Admin interface of CMS Software.

  If the TURN server is colocated with a CMS Web Bridge, the attacker could receive lookup messages for meeting conferences, which may contain call identifiers and passcodes for meetings.

  If the TURN server is colocated with a database node that is part of a CMS database cluster, an attacker could gain unauthenticated access to the database for that cluster.

  To exploit this vulnerability, the attacker must have valid credentials for and authenticate to the TURN server of the affected system.

  For additional information about configuring CMS TURN servers, refer to the “TURN Server” section of the Cisco Meeting Server Scalability & Resilience Server Deployment Guide.

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/en/US/docs/general/warranty/English/EU1KEN_.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/en/US/support/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

  This vulnerability is fixed in CMS Software Releases 2.0.16, 2.1.11, 2.2.6, and later. Customers should upgrade to the latest software release by visiting the Software Center on Cisco.com and navigating to Products > Conferencing > Video Conferencing > Multiparty Conferencing > Meeting Server.

  For information about the CMS software release model, refer to Cisco Meeting Server: End of maintenance and support 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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170913-cmsturn

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2017-September-13

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