ESB-2018.0916 - [Cisco] Cisco IOS XE: Modify arbitrary files - Existing account 2018-03-29

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2018.0916
         Cisco IOS XE Software Arbitrary File Write Vulnerability
                               29 March 2018

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Cisco IOS XE
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Modify Arbitrary Files -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-0196  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-wfw

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Cisco Security Advisory

Cisco IOS XE Software Arbitrary File Write Vulnerability

Medium

Advisory ID:     cisco-sa-20180328-wfw

First Published: 2018 March 28 16:00 GMT

Version 1.0:     Final

Workarounds:     No workarounds available

Cisco Bug IDs:
CSCvb22645

CVE-2018-0196

CWE-20

CVSS Score:
4.9  AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N/E:X/RL:X/RC:X

Summary

  o A vulnerability in the web-based user interface (web UI) of Cisco IOS XE
    Software could allow an authenticated, remote attacker to write arbitrary
    files to the operating system of an affected device.

    The vulnerability is due to insufficient input validation of HTTP requests
    that are sent to the web UI of the affected software. An attacker could
    exploit this vulnerability by sending a malicious HTTP request to the web
    UI of the affected software. A successful exploit could allow the attacker
    to write arbitrary files to the operating system of an affected device.

    There are no workarounds that address this vulnerability.

    This advisory is available at the following link:
    https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
    cisco-sa-20180328-wfw

Affected Products

  o Vulnerable Products

    This vulnerability affects Cisco devices that are running a vulnerable
    release of Cisco IOS XE Software, if the HTTP Server feature is enabled.
    The default state of the HTTP Server feature is version-dependent.

    For information about which Cisco IOS XE Software releases are vulnerable,
    consult the Cisco bug ID(s) at the top of this advisory.

    Assessing 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 http (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
    http (secure|server) command for a router that has the HTTP Server feature
    enabled:

        Router# show running-config | include http (secure|server)

        ip http server
        ip http secure-server

    Determining the Cisco IOS XE Software Release

    To determine which Cisco IOS XE Software release is running on a device,
    administrators can log in to the device, use the show version command in
    the CLI, and then refer to the system banner that appears. If the device is
    running Cisco IOS XE Software, the system banner displays Cisco IOS
    Software, Cisco IOS XE Software, or similar text.

    The following example shows the output of the command for a device that is
    running Cisco IOS XE Software Release 16.2.1 and has an installed image
    name of CAT3K_CAA-UNIVERSALK9-M:

        ios-xe-device# show version

        Cisco IOS Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version Denali 16.2.1, RELEASE SOFTWARE (fc1)
        Technical Support: http://www.cisco.com/techsupport
        Copyright (c) 1986-2016 by Cisco Systems, Inc.
        Compiled Sun 27-Mar-16 21:47 by mcpre
        .
        .
        .

    For information about the naming and numbering conventions for Cisco IOS XE
    Software releases, see the Cisco IOS and NX-OS Software Reference Guide.

    Products Confirmed Not Vulnerable

    No other Cisco products are currently known to be affected by this
    vulnerability.

    Cisco has confirmed that this vulnerability does not affect Cisco IOS
    Software, Cisco IOS XR Software, or Cisco NX-OS Software.

Workarounds

  o There are no workarounds that address this vulnerability.

Fixed Software

  o For detailed information about fixed software releases, consult the Cisco
    bug ID(s) at the top of this advisory.

    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.

    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.

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.

Source

  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

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-wfw

Revision History

  o 
    +----------+----------------------------+----------+---------+----------------+
    | Version  |        Description         | Section  | Status  |      Date      |
    +----------+----------------------------+----------+---------+----------------+
    | 1.0      | Initial public release.    | --       | Final   | 2018-March-28  |
    +----------+----------------------------+----------+---------+----------------+

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