Cisco Webex vulnerabilities may enable attackers to covertly join meetings

Cisco has fixed three bugs in its Cisco Webex video conferencing offering that may allow attackers to:

• Join Webex meetings without appearing in the participant list (CVE-2020-3419)
• Covertly maintain an audio connection to a Webex meeting after being expelled from it (CVE-2020-3471)
• Gain access to information (name, email, IP address, device info) on meeting attendees without being admitted to the meeting (CVE-2020-3441)

About the Cisco Webex vulnerabilities

The three flaws were discovered by IBM researchers, after the company’s research department and the Office of the CISO decided to analyze their primary tool for remote meetings (i.e., Cisco Webex).

“These vulnerabilities work by exploiting the handshake process that Webex uses to establish a connection between meeting participants,” the researchers shared.

“These flaws affect both scheduled meetings with unique meeting URLs and Webex Personal Rooms. Personal rooms may be easier to exploit because they are often based on a predictable combination of the room owner’s name and organization name. These technical vulnerabilities could be further exploited with a combination of social engineering, open source intelligence (OSINT) and cognitive overloading techniques.”

The vulnerabilities can all be exploited by unauthenticated, remote attackers, either by sending crafted requests to a vulnerable Cisco Webex Meetings or Cisco Webex Meetings Server site or by browsing the Webex roster.

More details about the possible attacks are available in this blog post, though details about the flaws will be limited until more users are able to implement the provided updates/patches.

Patches and security updates

The bugs affect both Cisco Webex Meetings sites (cloud-based) and Cisco Webex Meetings Server (on-premises).

Cisco addressed them in Cisco Webex Meetings sites a few days ago and no user action is required.

Users of Cisco Webex Meetings Server are advised to upgrade to 3.0MR3 Security Patch 5 or 4.0MR3 Security Patch 4, which contain the needed fixes.

CVE-2020-3419 also affects all Cisco Webex Meetings apps releases 40.10.9 and earlier for iOS and Android, so users are urged to implement the provided updates.