Summary

• A vulnerability in the application-hosting subsystem of Cisco IOS XE Software could allow an authenticated, local attacker to elevate privileges to root on an affected device. The attacker could execute IOS XE commands outside the application-hosting subsystem Docker container as well as on the underlying Linux operating system. These commands could be run as the root user.

  The vulnerability is due to a combination of two factors: (a) incomplete input validation of the user payload of CLI commands, and (b) improper role-based access control (RBAC) when commands are issued at the command line within the application-hosting subsystem. An attacker could exploit this vulnerability by using a CLI command with crafted user input. A successful exploit could allow the lower-privileged attacker to execute arbitrary CLI commands with root privileges. The attacker would need valid user credentials to exploit this vulnerability.

  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-iosxe-iox-app-host-mcZcnsBt

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco IOS XE Software releases 16.12.1 and later with the Application Hosting feature enabled and the hosted application running.

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

  Determine the Device Configuration

  To determine whether the Application Hosting feature is enabled, assess the following conditions:

  Use the show running-config | include app-hosting appid command to determine whether app-hosting has been configured:

  Router# show running-config | include app-hosting appid
  app-hosting appid MYAPP

  Use the show app-hosting list command to determine whether the application referenced in the output of the preceding command is running:

  Router# show app-hosting list
  App id                                   State
  ---------------------------------------------------------
  MYAPP                                    RUNNING

  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 software:

  • IOS Software
  • IOS XR Software
  • NX-OS Software
  • Wireless LAN Controller Software

Details

• The Cisco Application Hosting feature extends the cloud to the edge of the network, enabling distributed data processing closer to the source. Application hosting on the switch provides efficient access to live network traffic and the rich telemetry supported by the infrastructure. This access enables administrators to host security, network monitoring/troubleshooting, and analytics tools without requiring expensive compute nodes. Application hosting also shortens the development cycle by allowing administrators to run off-the-shelf Docker apps.

  For additional information, see What is Application Hosting?

Workarounds

• There are no workarounds that address this vulnerability. To mitigate this vulnerability if application hosting is not needed, administrators can disable the Application Hosting feature or remove the configuration for the hosted applications.

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.

  For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to the Cisco IOS XE 2 Release Notes, Cisco IOS XE 3S Release Notes, or Cisco IOS XE 3SG Release Notes, depending on the Cisco IOS XE Software release.

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 by Victor Kamensky of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-iox-app-host-mcZcnsBt

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2020-SEP-24

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