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