[VulnWatch] Cisco Security Advisory: Access Point Web-Browser Interface Vulnerability

From: Cisco Systems Product Security Incident Response Team (psirt@private)
Date: Wed Jun 28 2006 - 10:00:00 PDT


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Cisco Security Advisory:  Access Point Web-Browser Interface
Vulnerability

=====================================================================

Advisory ID: cisco-sa-20062806-ap.shtml

http://www.cisco.com/warp/public/707/cisco-sa-20060628-ap.shtml

Revision 1.0
============

Contact PSIRT at psirt@private if you have any questions regarding
the receipt or use of this information.

For Public Release 2006 June 28 1700 UTC (GMT)

+--------------------------------------------------------------------

Contents
========

    Summary
    Affected Products
    Details
    Impact
    Software Version and Fixes
    Workarounds
    Obtaining Fixed Software
    Customers with Service Contracts
    Customers using Third Party Support Organizations
    Customers without Service Contracts
    Exploitation and Public Announcements
    Status of this Notice: DRAFT
    Distribution
    Revision History
    Cisco Security Procedures

+--------------------------------------------------------------------

Summary
=======

The Cisco web-browser interface for Cisco access points contains a
vulnerability that could, under certain circumstances, remove the
default security configuration from the managed access point and
allow administrative access without validation of administrative user
credentials.

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

There are workarounds available to mitigate the effects of this 
vulnerability.

This advisory is posted at: 
http://www.cisco.com/warp/public/707/cisco-sa-20060628-ap.shtml

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

Vulnerable Products
+------------------

The following access points are affected if running Cisco IOS version
12.3(8)JA or 12.3(8)JA1 and are configured for web-interface
management:

  * 350 Wireless Access Point and Wireless Bridge
   
  * 1100 Wireless Access Point
   
  * 1130 Wireless Access Point
   
  * 1200 Wireless Access Point
   
  * 1240 Wireless Access Point
   
  * 1310 Wireless Bridge
   
  * 1410 Wireless Access Point
   
To determine if web-interface management is enabled on a Cisco access
point, log into the device and issue the "show ip http server status"
command. If the output shows either 'http server status' or 'http 
secure server status' as "enabled", web-interface management is 
enabled. 

An example is shown below with web-interface management enabled:

         ap#show ip http server status
         HTTP server status: Enabled
         HTTP server port: 80
    [...lines removed...]
         HTTP secure server status: Disabled
         HTTP secure server port: 443
    [...lines removed...]

Web-interface management (HTTP server) is enabled by default.

To check the version of Cisco IOS running on the access point:

Via Browser: 
    Click on 'System Software menu'. The Cisco IOS version will be 
displayed in the field "System Software Version".

Via Command Line Interface (CLI): 
    To determine the software running on a Cisco access point, log
into the device and issue the "show version" command to display the
system banner.

Cisco IOS software will identify itself as "Internetwork Operating
System Software" or simply "IOS".

On the next line of output, the image name will be displayed between
parentheses, followed by "Version" and the Cisco IOS release name.

Other Cisco devices will not have the show version command or will
give different output.

The following example identifies a Cisco acess point running Cisco
IOS release 12.3(7)JA1 with an installed image name of C1200-K9W7-M:

    ap#show version
    Cisco IOS Software, C1200 Software (C1200-K9W7-M), 
    Version 12.3(7)JA1, RELEASE SOFTWARE (fc1)
    Technical Support: http://www.cisco.com/techsupport
    Copyright (c) 1986-2005 by Cisco Systems, Inc.
    Compiled Thu 06-Oct-05 09:40 by evmiller
    !
    [...lines removed...]
    !

Additional information about Cisco IOS release naming can be found
at: http://www.cisco.com/warp/public/620/1.html

Products Confirmed Not Vulnerable
+--------------------------------

  * Access Points that are not running Cisco IOS.
   
  * Access Points that are running any version of Cisco IOS other
    than 12.3(8)JA or 12.3(8)JA1.
   
  * Access Points with disabled web-interface management (Both HTTP
    and HTTP secure) are not vulnerable.

  * All Cisco access points running in lightweight mode.
   
Details
=======

The web-browser interface contains management pages that are used to
change the wireless device settings, upgrade firmware, and monitor
and configure other wireless devices on the network. 

The web-browser interface is enabled by default, and is indicated by
the configuration command "ip http server" or 
"ip http secure-server".

An access point running a default configuration will use the default
enable secret password for administrative access. This can be
modified via the web-browser interface tab 'Security --> Admin Access
- --> Default Authentication (Global Password)' or via the CLI with the
configuration command "enable secret [new_secret]".

"Local User List Only (Individual Passswords)" allows administrators
of the access points to define a local unique username/password
database for their administrators, so that a common global password
is not shared.

A vulnerability exists in the access point web-browser interface when
'Security --> Admin Access' is changed from: "Default Authentication
(Global Password)" to "Local User List Only (Individual Passwords)".

This results in the Access Point being re-configured with no
security, either Global Password or Individual Passwords, enabled.

This allows for open access to the Access Point via the web browser
interface or via the console port with no validation of user 
credentials.

Access points configured for "Local User List Only (Individual
Passwords)" and running non-vulnerable versions of Cisco IOS which
are subsequently upgraded to a vulnerable version of IOS are not
affected by this vulnerability as long as the configuration is not
altered after the upgrade.

This vulnerability is documented by Cisco Bug ID: 

CSCsd67403 -- Cannot Select Option to Authenticate using Local User
              List Only.

Impact
======

Successful exploitation of this vulnerability will result in 
unauthorized administrative access to the access point via the 
web management interface or via the console port.

Software Version and Fixes
==========================

When considering software upgrades, also consult 
http://www.cisco.com/go/psirt 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") or your contracted
maintenance provider for assistance.

Each row of the Cisco IOS software table (below) describes a release
train and the platforms or products for which it is intended. If a
given release train is vulnerable, then the earliest possible
releases that contain the fix (the "First Fixed Release") and the
anticipated date of availability for each are listed in the "Rebuild"
and "Maintenance" columns. 

A device running a release in the given train that is earlier than 
the release in a specific column (less than the First Fixed Release)
is known to be vulnerable. The release should be upgraded at least 
to the indicated release or a later version (greater than or equal
to the First Fixed Release label).

For more information on the terms "Rebuild" and "Maintenance,"
consult the following URL: 
http://www.cisco.com/warp/public/620/1.html.

+-------------------------------------------------------------------+
| Major Release |         Availability of Repaired Releases         |
|---------------+---------------------------------------------------|
|     12.3      |  Rebuild   |           Maintenance                |
|---------------+------------+--------------------------------------|
| 12.3(8)JA     | 12.3(8)JA2 | 12.3(11)JA; available 29th June 2006 |
|---------------+------------+--------------------------------------|
| 12.3(8)JA1    | 12.3(8)JA2 | 12.3(11)JA; available 29th June 2006 |
+-------------------------------------------------------------------+

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

Either of the following workarounds and mitigations may be used to
help mitigate the effects of this vulnerability:

  * Disable Web-Based Management:
   
    To prevent use of the web-browser interface via:

    Web-Based Management: 
      select the "Disable Web-Based Management" check box on the 
      'Services --> HTTP-Web Server' page and click "Apply".

    CLI: 
       Log into the device and issue the configuration commands
       (ensure to save the configuration upon exiting):
   
        ap(config)#no ip http server
        ap(config)#no ip http secure-server
        ap(config)#exit
   
  * Configure via CLI:
   
    Enabling "Local User List Only (Individual Passwords)" via the 
    CLI rather than the web-browser interface will provide the
    access point with the desired protected configuration. Log into
    the device and issue the configuration commands (ensure to save
    the configuration upon exiting):
   
        ap#configure terminal
        ap(config)#!setup the username password pair first
        ap(config)#username test privilege 15 password test
        ap(config)#!enable AAA
        ap(config)#aaa new-model
        ap(config)#!enable aaa authentication to local database
        ap(config)#aaa authentication login default local
        ap(config)#!enable aaa authorization to local database
        ap(config)#aaa authorization exec default local
        ap(config)#!Enable http authentication to AAA.
        ap(config)#ip http authentication aaa
        ap(config)#exit
   
  * Configure Radius/Tacacs Server first:
   
    Via the web-browser interface enabling any radius/tacacs+ server
    within 'Security --> Server Manager --> Corporate Servers' and
    then performing the option of 'Security --> Admin Access' as 
    "Local User List Only (Individual Passwords)" will provide a 
    work around to this vulnerability.
   
Obtaining Fixed Software
========================

Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed
software becomes available. Prior to deploying software, customers
should consult their maintenance provider or check the software for
feature set compatibility and known issues specific to their
environment.

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.

Do not contact either "psirt@private" or "security-alert@private"
for software upgrades.

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 http://www.cisco.com.

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 guidance and assistance
with the appropriate course of action in regards to this advisory.
The effectiveness of any workaround or fix is dependent on specific
customer situations such as product mix, network topology, traffic
behavior, and organizational mission. Due to the variety of affected
products and releases, customers should consult with their service
provider or support organization to ensure any applied workaround or
fix is the most appropriate for use in the intended network before it
is deployed.

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@private

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.

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including special localized
telephone numbers and instructions and e-mail addresses for use in
various languages.

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

A stand-alone copy or Paraphrase of the text of this document 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-20060628-ap.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@private
  * first-teams@private
  * bugtraq@private
  * vulnwatch@private
  * cisco@private
  * cisco-nsp@private
  * full-disclosure@private
  * comp.dcom.sys.cisco@private

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 1.0 | 2006-June-28 | Initial public 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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