A highly critical remote code execution vulnerability, tracked as CVE-2017-6753, was discovered in the Cisco Systems WebEx browser extension for Chrome and Firefox which has ~20M active users, and is part of Cisco’s popular web conferencing software.
This is the second time this year a critical vulnerability has been discovered in this product which even led to Google and Mozilla temporarily removing the add-on from their stores the first time.
“The vulnerability could allow an unauthenticated, remote attacker to execute arbitrary code with the privileges of the affected browser on an affected system. This vulnerability affects the browser extensions for Cisco WebEx Meetings Server, Cisco WebEx Centers (Meeting Center, Event Center, Training Center, and Support Center), and Cisco WebEx Meetings when they are running on Microsoft Windows.” stated by the security advisory published by CISCO.
The vulnerability is due to a design defect in the extension. An attacker who can convince an affected user to visit an attacker-controlled web page or follow an attacker-supplied link with an affected browser could exploit the vulnerability. If successful, the attacker could execute arbitrary code with the privileges of the affected browser.
The vulnerability was discovered by the popular Google Project Zero hacked Tavis Ormandy and Cris Neckar of Divergent Security.
There are no workarounds that address this vulnerability. However, Mac users may use Safari to join WebEx meetings because Safari is not affected by this vulnerability. Windows users may use Internet Explorer and administrators and users of Windows 10 systems may use Microsoft Edge to join and participate in WebEx sessions because Microsoft Internet Explorer and Microsoft Edge are not affected by this vulnerability.