A vulnerability in Cisco WebEx Business Suite clients, Cisco WebEx Meetings, and Cisco WebEx Meetings Server could allow an authenticated, remote attacker to execute arbitrary code on a targeted system. The vulnerability is due to insufficient input validation by the Cisco WebEx clients. An attacker could exploit this vulnerability by providing meeting attendees with a malicious Flash (.swf) file via the file-sharing capabilities of the client. Exploitation of this vulnerability could allow arbitrary code execution on the system of a targeted user. 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-20180418-wbs
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
The following client builds of Cisco WebEx Business Suite (WBS31 and WBS32), Cisco WebEx Meetings, and Cisco WebEx Meetings Server address the vulnerability described in this advisory:
To determine whether a Cisco WebEx meeting site is running an affected version of the WebEx client build, users can log in to their Cisco WebEx meeting site and go to the Support > Downloads section. The version of the WebEx client build will be displayed on the right side of the page under About Meeting Center. Cisco WebEx software updates are cumulative in client builds. For example, if client build 30.32.16 is fixed, build 30.32.17 will contain updated software.
Note: Users with Cisco WebEx Business Suites that are on lockdown will need to contact WebEx Support to apply the appropriate patch to their WebEx site.
Note: Upon updating to the most current client build of the WebEx Suites, customers will no longer be able to share Flash (.swf) files by using the WebEx file-sharing feature.
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.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.3 | Modified wording to reflect that the vulnerability lies in the file-sharing functionality, not the file-transfer capability embedded in WebEx. | Summary, Details, Fixed Software | Final | 2018-May-02 |
| 1.2 | Modified wording to reflect that the vulnerability lies in the file-transfer functionality, not the file-sharing capability embedded in WebEx. | Summary, Details, Fixed Software | Final | 2018-April-25 |
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