Summary

• Multiple vulnerabilities in Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated attacker with Administrator-level read-only credentials to elevate their privileges to Administrator with read-write credentials on an affected system.

  Note: "Cisco Expressway Series" refers to Cisco Expressway Control (Expressway-C) devices and Cisco Expressway Edge (Expressway-E) devices.

  For more information about these vulnerabilities, see the Details section of this advisory.

  Cisco has released software updates that address these vulnerabilities. There are workarounds that address one of these vulnerabilities.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-expressway-priv-esc-Ls2B9t7b

Affected Products

• Vulnerable Products

  These vulnerabilities affect Cisco Expressway Series and Cisco TelePresence VCS.

  The vulnerability described in CVE-2023-20192 only affects Cisco Expressway Series and Cisco TelePresence VCS if they are running a vulnerable release and have granted CLI access to a read-only administrator of the system.

  For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

  Products Confirmed Not Vulnerable

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

Details

• The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit the other vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerability.

  Details about the vulnerabilities are as follows:

  CVE-2023-20105: Cisco Expressway Series and Cisco TelePresence VCS Privilege Escalation Vulnerability

  A vulnerability in the change password functionality of Cisco Expressway Series and Cisco TelePresence VCS could allow an authenticated, remote attacker with Administrator-level read-only credentials to elevate their privileges to Administrator with read-write credentials on an affected system.

  This vulnerability is due to incorrect handling of password change requests. An attacker could exploit this vulnerability by authenticating to the application as a read-only administrator and sending a crafted request to the web-based management interface. A successful exploit could allow the attacker to alter the passwords of any user on the system, including an administrative read-write user, and then impersonate that user.

  Note: "Cisco Expressway Series" refers to Cisco Expressway Control (Expressway-C) devices and Cisco Expressway Edge (Expressway-E) devices.

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

  Bug ID(s): CSCvz54058
  CVE ID: CVE-2023-20105
  Security Impact Rating (SIR): Critical
  CVSS Base Score: 9.6
  CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

  CVE-2023-20192: Cisco Expressway Series and Cisco TelePresence VCS Privilege Escalation Vulnerability

  A vulnerability in the privilege management functionality of Cisco Expressway Series and Cisco TelePresence VCS could allow an authenticated, local attacker with Administrator-level read-only CLI credentials to elevate their privileges to Administrator with read-write credentials on an affected system.

  This vulnerability is due to incorrect implementation of user role permissions. An attacker could exploit this vulnerability by authenticating to the application as a read-only CLI administrator and issuing commands normally reserved for administrators with read-write capabilities. A successful exploit could allow the attacker to execute commands beyond the sphere of their intended access level, including modifying system configuration parameters.

  Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

  Bug ID(s): CSCwf28030
  CVE ID: CVE-2023-20192
  Security Impact Rating (SIR): High
  CVSS Base Score: 8.4
  CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

Workarounds

• There is a workaround that addresses one of these vulnerabilities.

  Workaround for CVE-2023-20192: Disable CLI access for read-only users.

  Note: CLI access is disabled by default for read-only administrators.

  While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.

  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.

  The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.

  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 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

  In the following table, the left column lists Cisco software releases. The center and right columns indicate whether a release is affected by the vulnerabilities that are described in this advisory and the first release that includes the fix for these vulnerabilities. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.

  Cisco Expressway Series and Cisco TelePresence VCS Release	First Fixed Release for CVE-2023-20105	First Fixed Release for CVE-2023-20192
  Earlier than 14.0	Migrate to a fixed release.	Not vulnerable.
  14.0	14.2.1	14.3.0

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

• The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

Source

• CVE-2023-20105: This vulnerability was found during internal security testing by Jason Crowder of the Cisco Advanced Security Initiatives Group (ASIG).

  CVE-2023-20192: This vulnerability was found during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-expressway-priv-esc-Ls2B9t7b

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2023-JUN-07

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