Summary

• Multiple vulnerabilities in the web-based user interface (Web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker to execute commands with elevated privileges on the affected device.

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

  Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-webui-cmd-injection

  This advisory is part of the September 25, 2019, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 12 Cisco Security Advisories that describe 13 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: September 2019 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  These vulnerabilities affect Cisco devices that are running a vulnerable IOS XE Software release with the HTTP Server feature enabled.

  The default state of the HTTP Server feature is version dependent.
  
  For information about which Cisco IOS XE Software releases are vulnerable, see the Fixed Software section of this advisory.

  Determining 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-server 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-server command for a device that has the HTTP Server feature enabled:

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

  The presence of either command in the device configuration indicates that the HTTP Server feature is enabled.

  If the output from the previous command also contains:

  ip http active-session-modules none
  ip http secure-active-session-modules none

  The device is not affected by the vulnerabilities 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 these vulnerabilities.

  Cisco has confirmed that these vulnerabilities do not affect Cisco IOS Software, Cisco IOS XR Software, or Cisco NX-OS Software.

Details

• Multiple vulnerabilities in the web-based user interface (Web UI) of Cisco IOS XE Software could allow an authenticated attacker to execute arbitrary commands with elevated privileges on an affected device.

  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.

  Cisco IOS XE Software Web UI Low Privileged Command Injection Vulnerability

  A vulnerability in the web-based user interface (Web UI) of Cisco IOS XE Software could allow an authenticated but low-privileged attacker to execute Cisco IOS commands with elevated privileges (level 15) on an affected device. 

  The vulnerability exists because the affected software improperly sanitizes user-supplied input. An attacker could exploit this vulnerability by supplying a crafted input parameter on a form in the Web UI and then submitting that form. A successful exploit could allow the attacker to execute arbitrary Cisco IOS commands as a privilege level 15 user.

  The Common Vulnerabilities and Exposures (CVE) ID for this vulnerability is: CVE-2019-12651

  Cisco IOS XE Software WebUI Privileged Command Injection Vulnerability

  A vulnerability in the web-based user interface (Web UI) of Cisco IOS XE Software could allow an authenticated, remote attacker to execute commands on the underlying Linux shell of an affected device with root privileges.

  The vulnerability exists because the affected software improperly sanitizes user-supplied input. An attacker who has valid administrator-level access (level 15) to an affected device could exploit this vulnerability by supplying a crafted input parameter on a form in the Web UI and then submitting that form. A successful exploit could allow the attacker to run arbitrary commands on the device with root privileges, which may lead to complete system compromise.

  The Common Vulnerabilities and Exposures (CVE) ID for this vulnerability is: CVE-2019-12650

Workarounds

• There are no workarounds that address these vulnerabilities.

  Disabling the HTTP Server feature eliminates the attack vector for these vulnerabilities and may be a suitable mitigation until affected devices can be upgraded. Administrators can disable the HTTP Server feature by using the no ip http server or no ip http secure-server command in global configuration mode. If both http server and http-secure server are in use, then both commands are required to disable the HTTP Server feature.

  Limiting access to the HTTP Server to trusted networks will limit exposure to these vulnerabilities. The following example shows how to allow remote access to the HTTP Server from the trusted 192.168.0.0/24 network:

  !
  ip http access-class 75
  ip http secure-server
  !
  access-list 75 permit 192.168.0.0 0.0.0.255
  access-list 75 deny   any
  !

  Note: In newer versions of IOS XE Software, to apply the access list use the ip http access-class ipv4 75 command for the previous example. Cisco Guide to Harden Cisco IOS Devices provides additional information about how to harden the device and secure management access.

Fixed Software

• Cisco has released free software updates that address the vulnerabilities described in this advisory. 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.

  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.

  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 a tool, the Cisco IOS Software Checker, that identifies 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 this tool to perform the following tasks:

  • Initiate a search by choosing one or more releases from a drop-down list or uploading a file from a local system for the tool to parse
  • Enter the output of the show version command for the tool to parse
  • Create a custom search by including all previously published Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication

  To determine whether a release is affected by any published Cisco Security Advisory, use the Cisco IOS Software Checker on Cisco.com or enter a Cisco IOS or IOS XE Software release—for example, 15.1(4)M2 or 3.13.8S—in the following field:

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

  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

• Cisco would like to thank Tahir Khan of Verizon for finding and reporting the vulnerability identified as CVE-2019-12651. The vulnerability identified as CVE-2019-12650 was found by ASIG – XB of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-webui-cmd-injection

Revision History

• Version	Description	Section	Status	Date
  1.2	Added link to IPSignature.	Sidebar	Final	2019-October-11
  1.1	CLI command output update.	Vulnerable Products	Final	2019-September-30
  1.0	Initial public release.	—	Final	2019-September-25

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