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             AUSCERT External Security Bulletin Redistribution

         Cisco Webex Meetings and Cisco Webex Meetings Server Host
                      Key Brute Forcing Vulnerability
                              14 January 2021


        AusCERT Security Bulletin Summary

Product:           Cisco Webex Meetings
                   Cisco Webex Meetings Server
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Reduced Security -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-1311  

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

Cisco Webex Meetings and Cisco Webex Meetings Server  Host Key Brute Forcing

Priority:        Medium
Advisory ID:     cisco-sa-webex-brutef-hostkey-FWRMxVF
First Published: 2021 January 13 16:00 GMT
Version 1.0:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCvv72420 CSCvv84319
CVE Names:       CVE-2021-1311
CWEs:            CWE-307


  o A vulnerability in the reclaim host role feature of Cisco Webex Meetings
    and Cisco Webex Meetings Server could allow an authenticated, remote
    attacker to take over the host role during a meeting.

    This vulnerability is due to a lack of protection against brute forcing of
    the host key. An attacker could exploit this vulnerability by sending
    crafted requests to a vulnerable Cisco Webex Meetings or Webex Meetings
    Server site. A successful exploit would require the attacker to have access
    to join a Webex meeting, including applicable meeting join links and
    passwords. A successful exploit could allow the attacker to acquire or take
    over the host role for a meeting.

    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:

Affected Products

  o Vulnerable Products

    This vulnerability affected all Cisco Webex Meetings sites prior to
    December 15, 2020. Webex Meetings is cloud based.

    At the time of publication, this vulnerability also affected the following
    releases of Cisco Webex Meetings Server, which is on premises. See the
    Details section in the bug ID(s) at the top of this advisory for the most
    complete and current information.

       3.0MR3 Security Patch 5 and earlier
       4.0MR3 Security Patch 4 and earlier

    Products Confirmed Not Vulnerable

    Only products listed in the Vulnerable Products section of this advisory
    are known to be affected by this vulnerability.


  o There are no workarounds that address this vulnerability.

Fixed Software

  o 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

    Fixed Releases

    Cisco has addressed this vulnerability in Cisco Webex Meetings sites, which
    are cloud based. No user action is required.

    At the time of publication, the following releases for Cisco Webex Meetings
    Server, which is on-premises software, contained the fix for this
    vulnerability. Customers are advised to apply updated software releases.
    See the Details section in the bug ID(s) at the top of this advisory for
    the most complete and current information.

       3.0MR3 Security Patch 6
       4.0MR3 Security Patch 5

    Customers who need additional information are advised to contact the Cisco
    TAC or their contracted maintenance providers.

Exploitation and Public Announcements

  o 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.


  o Cisco would like to thank Nabeel Ahmed and Tom Wyckhuys of NTT Belgium for
    reporting this vulnerability.

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.


  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-brutef-hostkey-FWRMxVF

Revision History

  o +----------+---------------------------+----------+--------+--------------+
    | Version  |        Description        | Section  | Status |     Date     |
    | 1.0      | Initial public release.   | -        | Final  | 2021-JAN-13  |

- --------------------------END INCLUDED TEXT--------------------

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