Summary

• A vulnerability in the CLI of Cisco IOS XE SD-WAN Software could allow an authenticated, local attacker to execute arbitrary commands with elevated privileges.

  This vulnerability is due to insufficient input validation by the system CLI. An attacker with privileges to run commands could exploit this vulnerability by first authenticating to an affected device using either local terminal access or a management shell interface and then submitting crafted input to the system CLI. A successful exploit could allow the attacker to execute commands on the underlying operating system with root-level privileges. An attacker with limited user privileges could use this vulnerability to gain complete control over the system.

  Note: For additional information about specific impacts, see the Details section of this advisory.

  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:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-sdwan-VQAhEjYw

  This advisory is part of the March 2023 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2023 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running a vulnerable release of universal Cisco IOS XE Software in controller mode or a vulnerable release of standalone Cisco IOS XE SD-WAN Software:

  • 1000 Series Integrated Services Routers (ISRs)
  • 4000 Series ISRs
  • ASR 1000 Series Aggregation Services Routers
  • Catalyst 8000 Edge Platforms Family
  • Cloud Services Router (CSR) 1000V Series

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

  Note: The standalone Cisco IOS XE SD-WAN Software release images are separate from the universal Cisco IOS XE Software release images. The SD-WAN feature was first integrated into universal Cisco IOS XE Software with Release 17.2.1r. For more information, see the Cisco SD-WAN Getting Started Guide.

  Determine the Device Configuration

  There are two methods for determining whether the controller mode is enabled on a device that is running universal Cisco IOS XE Software. A device must be in controller mode to use the Cisco SD-WAN feature.

  Option 1: Use the show running-config | include sdwan Command

  To determine whether the controller mode is enabled on a device, use the show running-config | include sdwan command and check the tunnel mode in the output. If the command returns tunnel mode sdwan, the SD-WAN feature is enabled. Therefore, the device is in controller mode and is considered vulnerable. If the command returns no output or the command does not exist, the device is not affected by this vulnerability.

  The following example shows the output of the show running-config | include sdwan command on a device that is in controller mode:

  Router# show running-config | include sdwan
  tunnel mode sdwan
  Router#

  Option 2: Use the show version Command

  Alternatively, use the show version command to determine whether the device is in controller mode. The end of the output includes the router operating mode, which indicates whether the device is in controller mode.

  The following example shows part of the show version command output on a device that is in controller mode:

  Router# show version
  .
  .
  .
  Router operating mode: Controller-Managed
  .
  .
  .

  Products Confirmed Not Vulnerable

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

  Cisco has confirmed that this vulnerability does not affect the following Cisco products or platforms:

  • IOS Software
  • IOS XE Software in autonomous mode
  • IOS XR Software
  • Meraki products
  • NX-OS Software
  • SD-WAN vBond Orchestrator Software
  • SD-WAN vEdge Routers
  • SD-WAN vEdge Cloud Routers
  • SD-WAN vManage Software
  • SD-WAN vSmart Controller Software

Details

• The impact of exploitation may differ depending on the user access privilege levels on an affected device.

  The Security Impact Rating (SIR) for this vulnerability is High for affected devices where low-privileged users are authorized to log in and run command line operations. In this scenario, a user with limited privileges could exploit this vulnerability to gain complete control over the affected device.

  Potential impacts are lower for affected devices where only high-privileged administrative users are authorized to log in. An administrative user gains fewer privileges through exploitation of this vulnerability, reducing the impact.

Workarounds

• There are no workarounds that address this vulnerability.

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.

  Cisco IOS and IOS XE Software

  To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).

  To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to determine whether a release is affected by any Cisco Security Advisory. To use the form, follow these steps:

  1. Choose which advisories the tool will search-only this advisory, only advisories with a Critical or High Security Impact Rating (SIR), or all advisories.
  2. Enter a release number-for example, 15.9(3)M2 or 17.3.3.
  3. Click Check.

  
  

  Only this advisory All Critical and High advisories All advisories

Exploitation and Public Announcements

• 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.

Source

• This vulnerability was found during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-sdwan-VQAhEjYw

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2023-MAR-22

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