Summary

• A vulnerability in the web-based user interface (web UI) of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to bypass access control restrictions on an affected device.

  The vulnerability is due to the presence of a proxy service at a specific endpoint of the web UI. An attacker could exploit this vulnerability by connecting to the proxy service. An exploit could allow the attacker to bypass access restrictions on the network by proxying their access request through the management network of the affected device. As the proxy is reached over the management virtual routing and forwarding (VRF), this could reduce the effectiveness of the bypass.

  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-webui-unauthprxy-KXXsbWh

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco IOS XE Software when the web UI is enabled.

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

  Determine the HTTP Server Configuration

  To determine whether the HTTP Server feature is enabled for a device, administrators can log in to the device and use the show running-config | include ip http server|secure|active command in the CLI to check for the presence of the ip http server command or the ip http secure-server command in the global configuration. If either command is present and configured, the HTTP Server feature is enabled for the device.

  The following example shows the output of the show running-config | include ip http server|secure|active command for a device that has the HTTP Server feature enabled:

  Router# show running-config | include ip http server|secure|active
  
  ip http server
  ip http secure-server

  Note: The presence of either command, or both commands, in the device configuration indicates that the web UI feature is enabled.

  If the ip http server command is present and the configuration also contains ip http active-session-modules none, the vulnerability is not exploitable over HTTP.

  If the ip http secure-server command is present and the configuration also contains ip http secure-active-session-modules none, the vulnerability is not exploitable over HTTPS.

  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:

  • IOS Software
  • IOS XR Software
  • NX-OS Software

Workarounds

• There are no workarounds that address this vulnerability.

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 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.

  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 during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webui-unauthprxy-KXXsbWh

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2020-JUN-03

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