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AUSCERT External Security Bulletin Redistribution
Cisco Webex Meetings Enumeration Attack
2 October 2019
AusCERT Security Bulletin Summary
Product: Cisco Webex Meetings
Publisher: Cisco Systems
Operating System: Windows
UNIX variants (UNIX, Linux, OSX)
Impact/Access: Access Confidential Data -- Remote/Unauthenticated
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Cisco Webex Meetings Enumeration Attack
Advisory ID: cisco-sa-20191001-webex-enum
First Published: 2019 October 1 13:00 GMT
Version 1.0: Final
o Cisco Webex Meetings is an enterprise solution for hosting online meetings
that offers video conferencing, screen sharing, and webinar capabilities
that support hundreds of participants. Cisco Webex Meetings utilizes a
nine-digit number as a user-friendly meeting identifier that can be easily
typed in to join a meeting from all types of endpoints.
On July 24th, 2019, Shreyans Mehta of Cequence Security and the CQ Prime
Research Team reported to Cisco that an attacker could take advantage of
one of the Webex Meetings API calls to enumerate all the meeting numbers in
use by an organization on the platform at a certain moment in time.
This advisory is available at the following link:
o Vulnerable Products
The issue described in this advisory affects Cisco Webex Meetings.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this attack method.
Cisco has confirmed that Cisco Webex Meeting Server, used for on-premise
deployments, does not exhibit this behavior.
o As part of the process of creating a meeting, Webex will randomly generate
and assign a nine-digit identifier that invitees can later use to join the
Shreyans Mehta of Cequence Security and the CQ Prime Research Team have
reported to Cisco that one of the Webex API calls could be used to
enumerate all of the meeting numbers for ongoing or future meetings. The
response to the invoked API call would allow an attacker to determine:
Whether a certain meeting number is in use, and
Whether the meeting is password protected
The attacker could use the gathered information to try to join meetings
that are not password protected. If the attacker was to join the meeting
using this information, they would still be listed as a participant and
could be expelled by the host. For password-protected meetings, the
attacker could recover the meeting number, but would not be able to uncover
the meeting title, schedule or host name, or join the meeting.
o The most effective step to strengthen the security of all meetings is to
require a password. Passwords protect against unauthorized attendance
because only users with access to the password are able to join.
Cisco recommends that administrators maintain their sites with the default
configuration that makes using a password mandatory when users are setting
up a meeting. This recommendation, with other security best practices, is
documented in the guide Cisco WebEx Best Practices for Secure Meetings for
Site Administrators and Hosts .
Cisco Webex offers a default, randomly generated password as part of the
meeting setup process in sites that do not mandate password protection.
Customers are able to override this password with a user-defined password
or disable password protection if the site allows it.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any malicious use of the attack method that is described in this advisory.
o Cisco would like to thank Shreyans Mehta of Cequence Security and the CQ
Prime Research Team for reporting this attack method.
Cisco Security Vulnerability Policy
o 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 |
| 1.0 | Initial public release. | - | Final | 2019-October-01 |
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