Summary

• A vulnerability in the SSL implementation of the Cisco Intelligent Proximity solution could allow an unauthenticated, remote attacker to view or alter information shared on Cisco Webex video devices and Cisco collaboration endpoints if the products meet the conditions described in the Vulnerable Products section.

  The vulnerability is due to a lack of validation of the SSL server certificate received when establishing a connection to a Cisco Webex video device or a Cisco collaboration endpoint. An attacker could exploit this vulnerability by using man in the middle (MITM) techniques to intercept the traffic between the affected client and an endpoint, and then using a forged certificate to impersonate the endpoint. Depending on the configuration of the endpoint, an exploit could allow the attacker to view presentation content shared on it, modify any content being presented by the victim, or have access to call controls.

  This vulnerability does not affect cloud registered collaboration endpoints.

  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-proximity-ssl-cert-gBBu3RB

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running a vulnerable software release, have the Proximity feature enabled, and are used to connect to on-premises devices:

  • Cisco Intelligent Proximity application
  • Cisco Jabber
  • Cisco Webex Meetings
  • Cisco Webex Teams
  • Cisco Meeting App

  Determining if the Proximity Feature Is Enabled on the Clients

  The software clients listed above are affected by this vulnerability when they are configured with the Proximity feature. However, for an attacker to exploit this vulnerability, a collaboration endpoint would also need to have the Proximity feature enabled. More information regarding the configuration of the Proximity feature on the endpoints is available in the Details and Workarounds sections of this advisory.

  Cisco Intelligent Proximity Application

  The Proximity feature is always enabled and cannot be disabled.

  Cisco Jabber¹

  There are multiple methods to determine whether the Proximity feature is enabled in Cisco Jabber:

  1. In the Jabber configuration file jabber-config.xml, this feature is enabled if the following line is not present:

  <EnableProximity>false</EnableProximity>

  2. In the application's preferences, navigate to Video Device. This feature is enabled if Connect to nearest device automatically is selected.

  Cisco Webex Meetings¹

  In the application's preferences, navigate to Video Systems. This feature is enabled if Automatically discover nearby devices is selected.

  Cisco Webex Teams¹

  From the Cisco Webex Control Hub, navigate to Settings and scroll to Device Discovery. This feature is enabled if Allow the Webex Teams app to connect to on-premises registered device is selected.

  Cisco Meeting App

  The Proximity feature is always enabled and cannot be disabled.

  ¹ The title of the submenu and the description of the option may vary with the software version. This information is meant to provide a general indication of where to find the configuration option for the Proximity feature.

  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 Proximity clients when used to connect to cloud registered devices.

Details

• The Cisco Intelligent Proximity solution allows laptops, smartphones, or other handheld devices to automatically discover and connect to Cisco Webex video devices and collaboration endpoints. The features available to the client depend on the endpoint configuration, which will influence what can be exploited by an attacker.

  Configuration options can include any combination of the following:

  • Content share from clients: A client can present onto the screen of the collaboration endpoint. The shared contents are presented only on the collaboration endpoint and are not shared with other connected clients. A MITM could read or modify the contents of the presentation.
  • Content share to clients: The shared contents are presented on the screen of the collaboration endpoint and on any connected client devices. A MITM could see any ongoing presentation shared by other clients and alter the presentation contents viewed by the victim of the attack.
  • Call controls: A client can control the Cisco collaboration endpoint in the same way as if using the device's touch panel. For example, it is possible to send commands to control volume or dial others. A MITM could use this to dial in and listen in on the call, impersonate the victim, or view any commands sent by the victim to the collaboration endpoint, including dialed URIs.

Workarounds

• There are no workarounds that address this vulnerability.

  Mitigations

  Disabling the Proximity Pairing Feature

  The primary purpose of the collaboration endpoints is video and content sharing. Customers that don't require automatic endpoint discovery and connection can disable the Proximity pairing feature.

  Disabling the Proximity Pairing Feature on Cisco Webex Video Devices and on Cisco Collaboration Endpoints

  Sign in to the endpoint's web interface and navigate to Setup > Configuration, then go to Proximity > Mode. Setting Mode to Off will ensure that all the Proximity features are disabled. Alternatively, the different sub-services can be disabled, which will limit exposure accordingly.

  For the Cisco IX5000 Series, navigate to Configuration > Display Frequency and Proximity Sections. Setting Mode to Off will ensure that all the Proximity features are disabled. Alternatively, the different sub-services can be disabled, which will limit exposure accordingly.

  Note: Once this feature is disabled on an endpoint, direct interaction with the device is required to use it. The various Proximity clients will not be able to connect to the endpoints. However, this doesn't prevent client software from connecting to other endpoints that might have the feature enabled, thus not fully eliminating the risk of exploitation.

  Disabling the Automatic Discovery of Collaboration Endpoints on the Proximity Clients

  It is possible to disable the Proximity pairing in Cisco Jabber, Cisco Webex Teams, and Cisco Webex Meetings. The instructions for how to reach the configuration option for each respective client are listed in the Vulnerable Products section of this advisory.

  Note: Disabling this feature on the clients will not prevent external guests from connecting to the endpoint, thus not fully eliminating the risk of exploitation.

  Migration of the Collaboration Solution to the Cloud

  Customers that are entitled to use the cloud registered collaboration solution may migrate their environment from on-premises to cloud registered devices. The Cisco Intelligent Proximity solution for cloud registered devices is not affected by 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 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

  Cisco has released software updates that address this vulnerability only for the Cisco Intelligent Proximity Application. Other client solutions that support the Proximity feature have not been patched.

  The solution implemented to address this vulnerability relies on host fingerprint verification. To prevent exploitation of this vulnerability, both the proximity client and collaboration endpoint need to be upgraded.

  Client: Cisco Intelligent Proximity Application

  Cisco fixed this vulnerability in Cisco Intelligent Proximity Application releases 3.1.0 and later.

  Endpoints: Cisco Webex Video Devices and Cisco Collaboration Endpoints

  Cisco fixed this vulnerability in Cisco Collaboration Endpoint Software releases 9.14.3 and later.

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 Adam Shore for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-proximity-ssl-cert-gBBu3RB

Revision History

• Version	Description	Section	Status	Date
  1.1	Added fixed releases.	Fixed Software	Final	2021-JUL-15
  1.0	Initial public release.	—	Final	2020-MAR-04

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