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             AUSCERT External Security Bulletin Redistribution

        Cisco Network Convergence System 1000 Series TFTP Directory
                          Traversal Vulnerability
                             21 February 2019


        AusCERT Security Bulletin Summary

Product:           Cisco Network Convergence System 1000 Series
                   Cisco IOS XR Software
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Access Confidential Data -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-1681  

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

Cisco Network Convergence System 1000 Series TFTP Directory Traversal

Priority:        High

Advisory ID:     cisco-sa-20190220-ncs

First Published: 2019 February 20 16:00 GMT

Version 1.0:     Final

Workarounds:     No workarounds available

Cisco Bug IDs:   CSCvk32415



CVSS Score:


    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:

Affected Products

  o 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 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/
         Version      :
         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.


  o There are no workarounds that address this vulnerability.

Fixed Software

  o 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:

    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

    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:

    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

    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

  o 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.


  o This vulnerability was found during internal security testing.

Cisco Security Vulnerability Policy

  o To learn about Cisco security vulnerability disclosure policies and
    publications, see the Security Vulnerability Policy. This document also
    contains instructions for obtaining fixed software and receiving security
    vulnerability information from Cisco.

Subscribe to Cisco Security Notifications

  o Subscribe


  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/

Revision History

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

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