Summary

• A vulnerability in the package unbundle utility of Cisco IOS XE Software could allow an authenticated, local attacker to gain write access to some files in the underlying operating system.
  
  The vulnerability is due to insufficient validation of files submitted to the affected installation utility. An attacker could exploit this vulnerability by uploading a crafted file to an affected system and running the installation utility command. A successful exploit could allow the attacker to gain write access to some files in the underlying operating system, which could allow the attacker to override the write-accessible files and compromise the integrity of the system.
  
  To exploit this vulnerability, the attacker must have sufficient privileges to execute the appropriate commands. In a default configuration, the privilege 15 privilege is needed to exploit this vulnerability. As a secondary impact of this vulnerability, an attacker may be able to modify some files and obtain access to the underlying operating system shell without having to provide a valid license.
  
  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-20161115-iosxe

Affected Products

• Vulnerable Products

  This vulnerability affects the following products if they are running a vulnerable release of Cisco IOS XE Software:
  

  • Cisco 5700 Series Wireless LAN Controllers
  • Cisco Catalyst 3650 Series Switches
  • Cisco Catalyst 3850 Series Switches
  • Cisco Catalyst 4500E Series Switches
  • Cisco Catalyst 4500X Series Switches

  This vulnerability is not configuration-specific. All the preceding products are vulnerable if they are running an vulnerable release of Cisco IOS XE Software. For information about vulnerable software releases, consult the Cisco bug IDs at the top of this advisory.
  
  To exploit this vulnerability, the attacker must have privileged access to an affected system and must also be able transfer a crafted file and execute privileged commands on the system.
  
  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 command-line interface (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 XE Software or similar text.
  
  The following example shows the output of the show version command on a device that is running Cisco IOS XE Software Release 3.6.5E:

  Router> show version
  
  Cisco IOS Software, IOS-XE Software, Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version 03.06.05.E RELEASE SOFTWARE7 (fc2)
  Technical Support: http://www.cisco.com/techsupport
  Copyright (c) 1986-2016 by Cisco Systems, Inc.
  Compiled Thu 02-Jun-16 09:03 by prod_rel_team
  .
  .
  .

  For information about the naming and numbering conventions for Cisco IOS XE Software releases, see White Paper: 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.

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• For information about fixed software releases, consult the Cisco bug IDs at the top of this advisory.
  
  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

• 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 reported to Cisco by Maksim Malyutin of Digital Security Ltd.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161115-iosxe

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2016-November-15

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