[c-nsp] Cisco Security Advisory: Cisco Airespace Wireless LAN Controllers Allow Unencrypted Network Access

Wed Nov 2 10:00:00 EST 2005

Cisco Access Points operating in Lightweight Access Point Protocol (LWAPP) mode
may allow unauthenticated end hosts to send unencrypted traffic to a secure
network by sending frames from the Media Access Control (MAC) address of an
already authenticated end host.

Only the access points that are operating in LWAPP (i.e., controlled by a
separate Wireless LAN Controller) mode are affected. Access points that are
running in autonomous mode are not affected.

Cisco has made free software available to address this vulnerability for
affected customers.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20051102-lwapp.shtml

Affected Products
=================

Vulnerable Products

Cisco 1200, 1131, and 1240 series access points controlled by Cisco 2000 and
4400 series Airespace Wireless LAN (WLAN) Controllers that are running software
version 3.1.59.24 are affected by this vulnerability.

This issue is only applicable to deployments where there is a separate WLAN
controller. Any system without a separate WLAN controller is not vulnerable.

Products Confirmed Not Vulnerable

  * Access points other than Cisco 1200, 1131 and 1240 series are not affected.
  * Access points that are deployed without a separate WLAN controller are not
    affected.
  * Access points that are controlled by WLAN controllers other than Cisco 2000
    and 4400 series are not affected.
  * Access points that are controlled by WLAN controllers which are running a
    software version other than 3.1.59.24 are not affected.
  * Access points that are running in autonomous mode are not affected.
  * Access points that are running VxWorks are not affected.

No other Cisco products are currently known to be affected by these
vulnerabilities.

Details
=======

LWAPP is an open protocol for access point management. In this mode of
operation, a WLAN controller system is used to create and enforce policies
across multiple different lightweight access points. All functions essential to
WLAN operations are centrally controlled by WLAN controllers. In this mode of
operation, Cisco access points run a simplified version of Cisco IOS . It is
not possible to enter into configuration mode and configure access points
individually in this mode. More information on LWAPP mode of operation can be
found at the following URL: 
http://www.cisco.com/en/US/netsol/ns340/ns394/ns348/ns337/networking_solutions_white_paper0900aecd802c18ee.shtml

A Cisco access point running in LWAPP mode can be checked by issuing the
following command from the console.

    configure terminal

Access points running in LWAPP mode will not allow the user to enter into
configuration mode, but will return an error message instead as shown in the
following output.

      AP000e.8466.5786>enable
      AP000e.8466.5786#configure terminal
                        ^
      % Invalid input detected at '^' marker.

      AP000e.8466.5786#

The alternative to LWAPP mode is the autonomous mode of operation. In this
mode, the access points are configured individually and run either VxWorks or
Cisco IOS operating systems.

Cisco 1200, 1131 and 1240 series access points that are controlled by 2000 or
4400 WLAN controllers in LWAPP mode of operation may accept unencrypted traffic
from end hosts even when configured to encrypt traffic. Such traffic needs to
be sourced from the MAC address of a legitimate, already authenticated end
host. By exploiting this vulnerability, an attacker may send malicious traffic
into a secure network. Legitimate end hosts will still communicate with the
access point in an encrypted manner.

Only the access points that are running in LWAPP mode are affected by this
vulnerability. Access points that are running in autonomous mode are not
affected.

In LWAPP mode, access points download their software from the WLAN controller.
Therefore, a software upgrade on the WLAN controller is required to address
this vulnerability.

This issue is documented by the Cisco bug ID CSCsc11134.

Impact
======

Successful exploitation of the vulnerability may allow an attacker to send
malicious traffic to a secure wireless network via an access point that is
controlled by an affected WLAN controller.

Software Versions and Fixes
===========================

When considering software upgrades, please also consult http://www.cisco.com/en/US/products/products_security_advisories_listing.html 
and any subsequent advisories to determine exposure and a complete upgrade 
solution.

In all cases, customers should exercise caution to be certain the devices to be
upgraded contain sufficient memory and that current hardware and software
configurations will continue to be supported properly by the new release. If
the information is not clear, contact the Cisco Technical Assistance Center
("TAC") for assistance.

In LWAPP mode of operation, it is not possible to change the software on the
access points individually. Access points download their software from the WLAN
controller. Therefore, a software upgrade on the WLAN controller is required.
This issue is fixed in version 3.1.105.0 of WLAN controller software.

Obtaining Fixed Software
========================

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular
update channels. For most customers, this means that upgrades should be
obtained through the Software Center on Cisco's worldwide website at the
following URLs.

  * http://www.cisco.com/pcgi-bin/tablebuild.pl/2000_series_Wireless_LAN_controller for Cisco 2000 Series WLAN Controller
  * http://www.cisco.com/pcgi-bin/tablebuild.pl/4400_series_Wireless_LAN_controller for Cisco 4400 Series WLAN Controller

Customers using Third-party Support Organizations

Customers whose Cisco products are provided or maintained through prior or
existing agreement with third-party support organizations such as Cisco
Partners, authorized resellers, or service providers should contact that
support organization for assistance with the upgrade, which should be free of
charge.

Customers without Service Contracts

Customers who purchase direct from Cisco but who do not hold a Cisco service
contract and customers who purchase through third-party vendors but are
unsuccessful at obtaining fixed software through their point of sale should get
their upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC
contacts are as follows.

  * +1 800 553 2447 (toll free from within North America)
  * +1 408 526 7209 (toll call from anywhere in the world)
  * e-mail: tac at cisco.com

Please have your product serial number available and give the URL of this
notice as evidence of your entitlement to a free upgrade. Free upgrades for
non-contract customers must be requested through the TAC.

Please do not contact either "psirt at cisco.com" or "security-alert at cisco.com"
for software upgrades.

Customers may only install and expect support for the feature sets they have
purchased. By installing, downloading, accessing or otherwise using such
software upgrades, customers agree to be bound by the terms of Cisco's software
license terms found at http://www.cisco.com/public/sw-license-agreement.html,
or as otherwise set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Workarounds
===========

There are no workarounds for this issue.

Exploitation and Public Announcements
=====================================

The Cisco PSIRT is not aware of any public announcements or malicious use of
the vulnerability described in this advisory.

Status of This Notice: FINAL
============================

THIS ADVISORY IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF
GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF
THE INFORMATION ON THE ADVISORY OR MATERIALS LINKED FROM THE ADVISORY IS AT
YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS NOTICE AT ANY
TIME.

A stand-alone copy or paraphrase of the text of this security advisory that
omits the distribution URL in the following section is an uncontrolled copy,
and may lack important information or contain factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at 
http://www.cisco.com/warp/public/707/cisco-sa-20051102-lwapp.shtml.

In addition to worldwide web posting, a text version of this notice is
clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail
and Usenet news recipients.

  * cust-security-announce at cisco.com
  * first-teams at first.org (includes CERT/CC)
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's worldwide
website, but may or may not be actively announced on mailing lists or
newsgroups. Users concerned about this problem are encouraged to check the
above URL for any updates.

Revision History
================

+---------------------------------------------+
| Revision  | 2005-Nov-2 | Initial public     |
| 1.0       |            | release            |
+---------------------------------------------+

Cisco Security Procedures
=========================

Complete information on reporting security vulnerabilities in Cisco products,
obtaining assistance with security incidents, and registering to receive
security information from Cisco, is available on Cisco's worldwide website at
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
. This includes instructions for press inquiries regarding Cisco security
notices. All Cisco security advisories are available at 
http://www.cisco.com/go/psirt.

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