ESB-2018.3265.3 - UPDATE [Win] Cisco Webex Meetings Desktop App: Multiple vulnerabilities - 2018-11-28


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             AUSCERT External Security Bulletin Redistribution

                              ESB-2018.3265.3
          Cisco Webex Meetings Desktop App Update Service Command
                          Injection Vulnerability
                             28 November 2018

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Cisco Webex Meetings Desktop App
Publisher:         Cisco Systems
Operating System:  Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Increased Privileges            -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-15442  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181024-webex-injection

Revision History:  November 28 2018: Updated the vulnerable and fixed releases 
                                     of Cisco Webex Meetings Desktop App and 
                                     Cisco Webex Productivity Tools to reflect 
                                     that the fixed releases that were initially 
                                     delivered were still affected by an attack 
                                     that was later reported to Cisco.
                   October 26 2018: Updated the vulnerable and fixed releases 
                                    of the Cisco Webex Meetings Desktop App 
                                    to reflect that the fix has been backported 
                                    to the 33.5 code train. Documented the 
                                    availability of a proof-of-concept exploit.
                   October 25 2018: Initial Release

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Cisco Security Advisory

Cisco Webex Meetings Desktop App Update Service Command Injection Vulnerability

Priority:         High
Advisory ID:      cisco-sa-20181024-webex-injection
First Published:  2018 October 24 16:00 GMT
Last Updated:     2018 November 27 16:01 GMT
Version 2.0:      Final
Workarounds:      No workarounds available
Cisco Bug IDs:    CSCvk70841
                  CVE-2018-15442
                  CWE-78

CVSS Score:        Base 7.8

                   CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

Summary

  o A vulnerability in the update service of Cisco Webex Meetings Desktop App
    for Windows could allow an authenticated, local attacker to execute
    arbitrary commands as a privileged user.

    The vulnerability is due to insufficient validation of user-supplied
    parameters. An attacker could exploit this vulnerability by invoking the
    update service command with a crafted argument. An exploit could allow the
    attacker to run arbitrary commands with SYSTEM user privileges.

    While the CVSS Attack Vector metric denotes the requirement for an attacker
    to have local access, administrators should be aware that in Active
    Directory deployments, the vulnerability could be exploited remotely by
    leveraging the operating system remote management tools.

    Cisco has released software updates that address this vulnerability. There
    are no workarounds that address this vulnerability.

    After an additional attack method was reported to Cisco, the previous fix
    for this vulnerability was determined to be insufficient. A new fix was
    developed, and the advisory was updated on November 27, 2018, to reflect
    which software releases include the complete fix.

    This advisory is available at the following link:
    https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
    cisco-sa-20181024-webex-injection

Affected Products

  o Vulnerable Products

    This vulnerability affects all Cisco Webex Meetings Desktop App releases
    prior to 33.6.4, and Cisco Webex Productivity Tools Releases 32.6.0 and
    later prior to 33.0.6, when running on a Microsoft Windows end-user system.

    To determine whether a vulnerable version of Cisco Webex Meetings Desktop
    App is installed on a Windows machine, users can launch the Cisco Webex
    Meetings application and click the gear icon in the top right of the
    application window, then choose the About... menu entry; a popup window
    displaying the currently installed version will open. This is also
    documented in the article Check the Cisco Webex Meetings Desktop App
    Version.

    To determine whether a vulnerable version of Cisco Webex Productivity Tools
    is installed on a Windows machine, users can right-click the Webex
    Productivity Tools icon on the Windows taskbar and select About from the
    menu; a popup window displaying the currently installed version will open.
    This is also documented in the article Check the Cisco Webex Productivity
    Tools Version for Windows.

    Products Confirmed Not Vulnerable

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

Workarounds

  o There are no workarounds that address this vulnerability.

Fixed Software

  o 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

    Cisco Webex Meetings Desktop App (Cisco Webex Meetings Suite WBS33)

    This vulnerability is fixed in Cisco Webex Meetings Desktop App Release
    33.6.4 and later releases.

    Users can update the Cisco Webex Meetings Desktop App by launching the
    Cisco Webex Meetings application and clicking the gear icon in the top
    right of the application window and then choosing the Check for Updates 
    entry from the drop-down list. This is also documented in the article
    Update the Cisco Webex Meetings Desktop App.

    Administrators can update the Cisco Webex Meetings Desktop App for their
    user base by following the instructions available in the document IT
    Administrator Guide for Mass Deployment of the Cisco Webex Meetings Desktop
    App.

    Cisco Webex Productivity Tools (Cisco Webex Meetings Suite WBS32, WBS31)

    Cisco Webex Productivity Tools is an optional companion application that
    allows users to quickly schedule and join meetings from their desktop
    without the need to access the Meetings website. The application should not
    be confused with the Cisco Webex Meetings Client, which is the main client
    application that provides the core functionality to host or attend a Webex
    meeting. Cisco Webex Productivity Tools has been replaced with Cisco Webex
    Meetings Desktop App since Cisco Webex Meetings Release 33.2.0.

    This vulnerability is fixed in Cisco Webex Productivity Tools Release
    33.0.6 and later.

    Users can update the Cisco Webex Productivity Tools by launching the Cisco
    Webex Meetings application and clicking Settings in the top right of the
    application window and then choosing Check for Updates from the drop-down
    list. This is documented in more detail in the article Check for Cisco
    Webex Productivity Tools Updates for Windows.

    Administrators can update the Cisco Webex Productivity Tools for their user
    base by following the instructions available in the document IT
    Administrator Guide for Mass Deployment of the Cisco Webex Meetings Desktop
    App.

Exploitation and Public Announcements

  o The Cisco Product Security Incident Response Team (PSIRT) is aware that
    proof-of-concept exploit code is available for the vulnerability described
    in this advisory. The Cisco PSIRT is not aware of any malicious use of the
    vulnerability that is described in this advisory.

Source

  o Cisco would like to thank Ron Bowes and Jeff McJunkin of Counter Hack for
    reporting this vulnerability.

    Cisco would also like to thank the following researchers for independently
    reporting an additional attack that affected the previously fixed releases:

      - Timothy Ferrell
      - Steven Seeley (mr_me) of Source Incite working with iDefense Labs
      - Marcos Accossatto of SecureAuth
      - Ron Bowes of Counter Hack

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.

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
    cisco-sa-20181024-webex-injection

Revision History

  o 
    +---------+-----------------------+---------------+--------+------------------+
    | Version |      Description      |    Section    | Status |       Date       |
    +---------+-----------------------+---------------+--------+------------------+
    |         | Updated the           |               |        |                  |
    |         | vulnerable and fixed  |               |        |                  |
    |         | releases of Cisco     |               |        |                  |
    |         | Webex Meetings        | Summary,      |        |                  |
    |         | Desktop App and Cisco | Affected      |        |                  |
    |         | Webex Productivity    | Products,     |        |                  |
    | 2.0     | Tools to reflect that | Fixed         | Final  | 2018-November-27 |
    |         | the fixed releases    | Releases,     |        |                  |
    |         | that were initially   | Source        |        |                  |
    |         | delivered were still  |               |        |                  |
    |         | affected by an attack |               |        |                  |
    |         | that was later        |               |        |                  |
    |         | reported to Cisco.    |               |        |                  |
    +---------+-----------------------+---------------+--------+------------------+
    |         | Updated the           |               |        |                  |
    |         | vulnerable and fixed  |               |        |                  |
    |         | releases of the Cisco | Affected      |        |                  |
    |         | Webex Meetings        | Products,     |        |                  |
    |         | Desktop App to        | Fixed         |        |                  |
    | 1.1     | reflect that the fix  | Releases,     | Final  | 2018-October-25  |
    |         | has been backported   | Exploitation  |        |                  |
    |         | to the 33.5 code      | and Public    |        |                  |
    |         | train. Documented the | Announcements |        |                  |
    |         | availability of a     |               |        |                  |
    |         | proof-of-concept      |               |        |                  |
    |         | exploit.              |               |        |                  |
    +---------+-----------------------+---------------+--------+------------------+
    | 1.0     | Initial public        | --            | Final  | 2018-October-24  |
    |         | release.              |               |        |                  |
    +---------+-----------------------+---------------+--------+------------------+

Legal Disclaimer

  o THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
    OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
    FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
    OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
    THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

    A standalone copy or paraphrase of the text of this document that omits the
    distribution URL is an uncontrolled copy and may lack important information
    or contain factual errors. The information in this document is intended for
    end users of Cisco products.

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