Summary

• A vulnerability in Cisco IOx application hosting environment of Cisco IOS XE Software could allow an authenticated, remote attacker to inject commands into the underlying operating system as the root user.

  This vulnerability is due to incomplete validation of fields in the application packages loaded onto IOx. An attacker could exploit this vulnerability by creating a crafted application .tar file and loading it onto the device. A successful exploit could allow the attacker to perform command injection into the underlying operating system as the root user.

  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-iox-cmdinj-RkSURGHG

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco IOS XE Software releases 16.3.1 and later if they were configured with the Cisco IOx application hosting infrastructure.

  The Cisco IOx application hosting infrastructure is not enabled by default.

  See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  Assess the Cisco IOx Application Hosting Environment

  There are two methods for assessing the IOx application hosting environment:

  Option 1: Use the show iox-service Command

  To determine the status of IOx functionality, use the show iox-service command in privileged EXEC mode, as shown in the following example:

  Router#show iox-service
  
  IOx Infrastructure Summary:
  ---------------------------
  IOx service (CAF)         : Running
  IOx service (HA)          : Running
  IOx service (IOxman)      : Running
  Libvirtd                  : Running
  
  Router#

  The device is vulnerable if IOx service (CAF) is in the Running state. If any statement in the following list is true, the device is not affected by the vulnerability described in this advisory:

  • IOx service (CAF) is in the Not Running state
  • The show iox-service privileged EXEC mode command returns no output
  • The show iox-service privileged EXEC mode command returns an error

  Option 2: Use the iox Configuration Command

  As an alternative, check the running configuration for the iox configuration command, as shown in the following example:

  Router#sh run | include iox
  iox
  Router#

  The device is vulnerable if the output contains a line with only iox, as shown in the preceding example. If the iox configuration command does not return output or this command returns an error, the device is not affected by the vulnerability described in this advisory.

  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:

  • Other platforms that support Cisco IOx
  • IOS Software
  • IOS XR Software
  • NX-OS Software

Workarounds

• There are no workarounds that address this vulnerability.

  Cisco recommends that customers who do not want to use the Cisco IOx application hosting environment mitigate this vulnerability by disabling IOx permanently on the device by using the no iox configuration command.

  While this mitigation 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

• 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.

  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 to identify any Cisco Security Advisories that impact a specific software release and the earliest release that fixes the vulnerabilities described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified (“Combined First Fixed”).

  Customers can use the Cisco Software Checker to search advisories in the following ways:

  • Choose the software and one or more releases
  • Upload a .txt file that includes a list of specific releases
  • Enter the output of the show version command

  After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication.

  Customers can also use the following form to determine whether a release is affected by any Cisco Security Advisory by entering a Cisco IOS or IOS XE Software release—for example, 15.1(4)M2 or 3.13.8S:

  By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search.

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

• Cisco would like to thank Orange Group for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iox-cmdinj-RkSURGHG

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2021-MAR-24

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