Summary

• A vulnerability in the Plug-and-Play (PnP) subsystem of the Cisco Aironet 1800, 2800, and 3800 Series Access Points running a Lightweight Access Point (AP) or Mobility Express image could allow an unauthenticated, adjacent attacker to execute arbitrary code with root privileges.
  
  The vulnerability is due to insufficient validation of PnP server responses. The PnP feature is only active while the device does not contain a configuration, such as a first time boot or after a factory reset has been issued. An attacker with the ability to respond to PnP configuration requests from the affected device can exploit the vulnerability by returning malicious PnP responses. If a Cisco Application Policy Infrastructure Controller - Enterprise Module (APIC-EM) is available on the network, the attacker would need to exploit the issue in the short window before a valid PnP response was received. If successful, the attacker could gain the ability to execute arbitrary code with root privileges on the underlying operating system of the device.
  
  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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170503-cme

Affected Products

• Vulnerable Products

  Cisco has confirmed that the only vulnerable software version for this advisory is 8.3.102.0 on the following products running either the Lightweight AP Software or Mobility Express image:
  

  • Cisco Aironet 1800 Series Access Points
  • Cisco Aironet 2800 Series Access Points
  • Cisco Aironet 3800 Series Access Points

  To determine which version of Cisco Aironet Series Access Point Software is running on a device, administrators can use the controller web interface or the CLI.
  
  To use the web interface, log in to the web interface, choose Management > Software Update and then refer to the release number that appears at the top of the page.
  
  To use the CLI, issue the show version command and then refer to the value in the AP Running Image field of the command output. The following example shows the output of the command for a device running software version 8.3.102.0:
  
  

  AP# show version
  .
  .
  cisco AIR-AP3802E-B-K9 ARMv7 Processor rev 1 (v7l) with 1030528/668540K bytes of memory.
  Processor board ID RFDPP1BS497
  AP Running Image     : 8.3.102.0
  Primary Boot Image   : 8.3.102.0
  .
  .

  Products Confirmed Not Vulnerable

  Cisco has confirmed that this vulnerability does not affect any Cisco Aironet Access Point running IOS software.
  
  No other Cisco products are currently known to be 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:
  http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.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 upgrade 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:
  http://www.cisco.com/en/US/support/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 Aironet 1800, 2800, 3800 Access Points	First Fixed Release for This Vulnerability
  Prior to 8.0	Not vulnerable
  8.0	Not vulnerable
  8.1	Not vulnerable
  8.2	Not vulnerable
  8.3	8.3.112.0 (See Note)
  8.4	Not vulnerable

  
  Note - Version 8.3.111.0 is the first fixed version, but was deferred and replaced by 8.3.112.0.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170503-cme

Revision History

• Version	Description	Section	Status	Date
  1.1	Metadata update.	—	Final	2017-September-21
  1.0	Initial public release.	—	Final	2017-May-03

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