Summary

• A vulnerability in the TFTP service of Cisco Network Convergence System 1000 Series software could allow an unauthenticated, remote attacker to retrieve arbitrary files from the targeted device, possibly resulting in information disclosure.

  The vulnerability is due to improper validation of user-supplied input within TFTP requests processed by the affected software. An attacker could exploit this vulnerability by using directory traversal techniques in malicious requests sent to the TFTP service on a targeted device. An exploit could allow the attacker to retrieve arbitrary files from the targeted device, resulting in the disclosure of sensitive information.

  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-20190220-ncs

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco IOS XR Software releases prior to Release 6.5.2 for Cisco Network Convergence System 1000 Series devices when the TFTP service is enabled.

  Determining the Cisco IOS XR Software Release
  
  To determine which Cisco IOS XR Software release is running on a device and the name of the device on which it is running, administrators can log in to the device and use the show version command in the CLI. If the device is running Cisco IOS XR Software, Cisco IOS XR Software or similar text appears in the system banner. The name of the hardware product appears on the line after the location of the system image file.
  
  The following example shows the output of the show version command on a Cisco NCS-1001 Network Convergence System 1001 device that is running Cisco IOS XR Software Release 6.5.2:

  RP/0/RP0/CPU0:MYS-127#show version
  
  Cisco IOS XR Software, Version 6.5.2.30I Copyright (c) 2013-2018 by Cisco Systems, Inc.
  
  Build Information:
   Built By     : deenayak
   Built On     : Sat Jan 26 23:45:04 PST 2019
   Built Host   : iox-ucs-023
   Workspace    : /auto/iox-ucs-023-san2/prod/6.5.2.30I.SIT_IMAGE/ncs1001/ws
   Version      : 6.5.2.30I
   Location     : /opt/cisco/XR/packages/
  
  cisco NCS-1001 () processor
  System uptime is 2 days 14 hours 54 minutes

  Customers can run the following command to determine if the TFTP service is enabled and running on a Cisco Network Convergence System 1000 Series device. The device is not vulnerable if the TFTP service is not enabled, and the service is not enabled in default configurations.

  show processes all | in tftpd

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability. Other Cisco Network Convergence System series devices are not affected by this vulnerability.

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 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.

  Fixed Releases

  Cisco fixed this vulnerability in Cisco IOS XR Software Release 6.5.2 for Cisco Network Convergence System 1000 Series devices.

  Customers can download the software from the Software Center on Cisco.com by doing the following:

  1. Click Browse all
  2. Navigate to Optical Networking > Optical Data Center Interconnects > Network Convergence System 1000 Series > Network Convergence System 1001 or Network Convergence System 1002 > IOS XR Software
     
  3. Access releases by using the left pane of the Network Convergence System page

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-20190220-ncs

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2019-February-20

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