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Multiple Vulnerabilities in the Cisco Wireless LAN Controller and Cisco Lightweight APs



Cisco Security Advisory: Multiple Vulnerabilities in the Cisco Wireless LAN Controller and Cisco Lightweight Access Points
Cisco Security Advisory: Multiple Vulnerabilities in the Cisco Wireless LAN Controller and Cisco Lightweight Access Points



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Cisco Security Advisory: Multiple Vulnerabilities in the Cisco
Wireless LAN Controller and Cisco Lightweight Access Points

Advisory ID: cisco-sa-20070412-wlc

http://www.cisco.com/warp/public/707/cisco-sa-20070412-wlc.shtml 

Revision 1.0

For Public Release 2007 April 12 1600 UTC (GMT)

- ---------------------------------------------------------------------

Summary
======
The Cisco Wireless LAN Controller (WLC) manages Cisco Aironet access
points using the Lightweight Access Point Protocol (LWAPP). The WLC
contains multiple vulnerabilities that could result in a denial of
service (DoS) condition, information disclosure, or access control
list changes, or allow an attacker to gain full administrative
access.

Cisco has made free software available to address this vulnerability
for affected customers. There are workarounds available to mitigate
the effects of these vulnerabilities.

This advisory is posted at 
http://www.cisco.com/warp/public/707/cisco-sa-20070412-wlc.shtml. 

Affected Products
================
This section provides details on affected products.

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

This sections describes the vulnerable products.

Vulnerable Software
+------------------

The vulnerabilities addressed in this document affect versions 4.0,
3.2, and prior versions of the Wireless LAN Controller software. To
identify the first fixed version for a specific Cisco Bug ID, please
see the Software Versions and Fixes section of this advisory.

To determine the version of WLC running in a given environment, use
one of the following methods:

  * In the web interface, choose the Monitor tab, click Summary in
    the left-hand pane, and note the "Software Version."
  * From the command-line interface, type show sysinfo and note the
    "Product Version."

Vulnerable Hardware
+------------------

Wireless LAN Controllers

  * Cisco 4400 Series Wireless LAN Controllers
  * Cisco 2100 Series Wireless LAN Controllers
  * Cisco Wireless LAN Controller Module

Wireless Integrated Switches and Routers

  * Cisco Catalyst 6500 Series Wireless Services Module (WiSM)
  * Cisco Catalyst 3750 Series Integrated Wireless LAN Controllers
  * Cisco Wireless LAN Controller Module

Cisco Aironet Access Points

  * Cisco Aironet 1000 Series
  * Cisco Aironet 1500 Series

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

  * Cisco Aironet 1400 Series
  * Cisco Aironet 1300 Series
  * Cisco Aironet 1240 AG Series
  * Cisco Aironet 1230 AG Series
  * Cisco Aironet 1200 Series
  * Cisco Aironet 1130 AG Series
  * Cisco Aironet 1100 Series

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

Details
======
The Cisco Wireless LAN Controller (WLC) manages Cisco Aironet access
points using the Lightweight Access Point Protocol (LWAPP). This
protocol provides centralized management of wireless networks. The
WLC contains the following vulnerabilities:

Default SNMP Community Strings
+-----------------------------

The WLC uses the commonly known values of "public" and "private" for
its read-only and read-write SNMP community strings. This
vulnerability is documented by Cisco Bug ID CSCse02384.

Malformed Ethernet Traffic Crash
+-------------------------------

The WLC may crash in response to malformed Ethernet traffic. This
vulnerability is documented by Cisco Bug ID CSCsc90179.

Multiple NPU Lock-Up Vulnerabilities
+-----------------------------------

The Network Processing Unit (NPU) is responsible for handling traffic
within the WLC. It is possible to cause one or more NPUs to lock up
by sending certain types of traffic to an affected WLC. This traffic
includes crafted SNAP packets, malformed 802.11 traffic, and packets
with unexpected length values in certain headers.

Each NPU operates independently and serves two of the physical ports
on the WLC. A lock up in one NPU does not affect the others, so the
number of NPUs available and the configuration of the device
determine whether these vulnerabilities result in a partial or
complete inability to forward traffic. To clear a NPU lock up, the
WLC must be restarted. If the lock up condition prevents access to
the management interface, the restart must be performed via the
console port or service port.

Devices that implement the WLC functionality in software rather than
hardware do not contain a NPU and are not affected by these
vulnerabilities. These software-based devices are the 2000 Series
WLC, the 2100 Series WLC, and the Cisco Wireless LAN Controller
Module.

These vulnerabilities are documented by Cisco Bug IDs CSCsg36361
, CSCsg15901, and CSCsh10841.

Hard-Coded Service Password in Lightweight AP
+--------------------------------------------

The Cisco Aironet 1000 Series and 1500 Series Lightweight Access
Points contain a hard-coded service password that is used for
troubleshooting. This service account is only accessible via a
physical connection to the console port, but the password is common
to all units in these series. This vulnerability is documented by
Cisco Bug ID CSCsg15192.

WLAN ACL Does Not Persist Through Reboot
+---------------------------------------

The WLC contains a bug when processing WLAN ACLs that causes the WLAN
ACL configuration to be saved with an invalid checksum. When the
configuration is subsequently reloaded at boot time, the checksum
fails and the WLAN ACLs are not installed. This vulnerability is
documented by Cisco Bug ID CSCse58195.

Vulnerability Scoring Details
============================
Cisco is providing scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS).

Cisco will provide a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.

Cisco PSIRT will set the bias in all cases to normal. Customers are
encouraged to apply the bias parameter when determining the
environmental impact of a particular vulnerability.

CVSS is a standards based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.

Cisco has provided an FAQ to answer additional questions regarding
CVSS at 
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html. 

Cisco has also provided a CVSS calculator to help compute the
environmental impact for individual networks at 
http://intellishield.cisco.com/security/alertmanager/cvss. 

CSCsc90179 - WLC - Default SNMP Community Strings
+--------------------------------------------------

CVSS Base Score: 10
     Access Vector: Remote
     Access Complexity: Low
     Authentication: Not Required
     Confidentiality Impact: Complete
     Integrity Impact: Complete
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 8.3
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCsc90179 - WLC - Malformed Ethernet Traffic Crash
+--------------------------------------------------

CVSS Base Score: 3.3
     Access Vector: Remote
     Access Complexity: Low
     Authentication: Not Required
     Confidentiality Impact: None
     Integrity Impact: None
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 2.7
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCsg36361 - WLC - NPU Lock-Up Vulnerability
+-------------------------------------------

CVSS Base Score: 3.3
     Access Vector: Remote
     Access Complexity: Low
     Authentication: Not Required
     Confidentiality Impact: None
     Integrity Impact: None
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 2.7
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCsg15901 - WLC - NPU Lock-Up Vulnerability
+-------------------------------------------

CVSS Base Score: 3.3
     Access Vector: Remote
     Access Complexity: Low
     Authentication: Not Required
     Confidentiality Impact: None
     Integrity Impact: None
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 2.7
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCsh10841 - WLC - NPU Lock-Up Vulnerability
+-------------------------------------------

CVSS Base Score: 3.3
     Access Vector: Remote
     Access Complexity: Low
     Authentication: Not Required
     Confidentiality Impact: None
     Integrity Impact: None
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 2.7
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCsg15192 - Hard-Coded Service Password in Lightweight AP
+---------------------------------------------------------

CVSS Base Score: 5.6
     Access Vector: Local
     Access Complexity: High
     Authentication: Not Required
     Confidentiality Impact: Complete
     Integrity Impact: Complete
     Availability Impact: Complete
     Impact Bias: Normal

CVSS Temporal Score: 4.6
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed

CSCse58195 - WLC - WLAN ACL Does Not Persist Through Reboot
+----------------------------------------------------------

CVSS Base Score: 3.7
     Access Vector: Remote
     Access Complexity: High
     Authentication: Not Required
     Confidentiality Impact: Partial
     Integrity Impact: Partial
     Availability Impact: None
     Impact Bias: Normal

CVSS Temporal Score: 3.1
     Exploitability: Functional
     Remediation Level: Official Fix
     Report Confidence: Confirmed 

Impact
=====
Successful exploitation of these vulnerabilities may result in the
issues described in this section.

Default SNMP Community Strings
+-----------------------------

CSCse02384: This vulnerability allows authenticated, remote attackers
to utilize common credentials to read and modify the configuration of
the WLC via SNMP.

Malformed Ethernet Traffic Crash
+-------------------------------

CSCsc90179: This vulnerability may allow unauthenticated attackers on
a local network segment to crash the WLC, resulting in a DoS
condition.

Multiple NPU Lock-Up Vulnerabilities
+-----------------------------------

CSCsg36361: This vulnerability allows unauthenticated attackers on a
local wireless network segment to prevent the WLC from passing
traffic, resulting in either a partial or complete DoS condition.

CSCsg15901: This vulnerability allows unauthenticated attackers on a
local wireless network segment to prevent the WLC from passing
traffic, resulting in either a partial or complete DoS condition.

CSCsh10841: This vulnerability allows unauthenticated attackers on a
local wireless network segment to prevent the WLC from passing
traffic, resulting in either a partial or complete DoS condition.

Hard-Coded Service Password in Lightweight AP
+--------------------------------------------

CSCsg15192: This vulnerability allows an attacker with physical
access to take control of an affected lightweight access point.

WLAN ACL Does Not Persist Through Reboot
+---------------------------------------

CSCse58195: This vulnerability causes the WLAN ACL configuration to
be disregarded, resulting in a silent and unexpected change to the
security posture of a wireless network.

Software Versions 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 software table (below) describes the earliest
software version that contains the fix (the "First Fixed Release")
and the anticipated date of availability when fixes are not
available. A device running a version that is earlier than the First
Fixed Release is known to be vulnerable. The release should be
upgraded at least to the indicated version (greater than or equal to
the First Fixed Release label).

+---------------------------------------+
| Cisco Bug  |   First Fixed Releases   |
|     ID     |                          |
|------------+--------------------------|
| CSCse02384 | Fix available on April   |
|            | 19, 2007.                |
|------------+--------------------------|
| CSCsc90179 | 3.2.116.21, 4.0.155.0    |
|------------+--------------------------|
|            | 3.2.193.5, 4.0.206.0,    |
| CSCsg36361 | 4.1.x.x (release         |
|            | pending)                 |
|------------+--------------------------|
|            | 3.2.171.5, 4.0.206.0,    |
| CSCsg15901 | 4.1.x.x (release         |
|            | pending)                 |
|------------+--------------------------|
|            | 3.2.171.5, 4.0.206.0,    |
| CSCsh10841 | 4.1.x.x (release         |
|            | pending)                 |
|------------+--------------------------|
| CSCsg15192 | 3.2.185.0, 4.0.206.0     |
|------------+--------------------------|
| CSCse58195 | 4.0.206.0                |
+---------------------------------------+

Workarounds
==========
This section describes workarounds for these vulnerabilities.

Default SNMP Community Strings
+-----------------------------

Customers can mitigate this vulnerability by changing the SNMP
community strings from their default values. This can be accomplished
on each WLC by using the menu to access Management > SNMP >
Communities and then changing the values of the community strings. On
larger networks, the Cisco Wireless Control System can be used to
apply SNMP changes across multiple controllers simultaneously.

Malformed Ethernet Traffic Crash
+-------------------------------

There are no known workarounds for this vulnerability.

Multiple NPU Lock-Up Vulnerabilities
+-----------------------------------

There are no known workarounds for these vulnerabilities.

Hard-Coded Service Password in Lightweight AP
+--------------------------------------------

There are no known workarounds for this vulnerability.

WLAN ACL Does Not Persist Through Reboot
+---------------------------------------

There are no known workarounds for this vulnerability.

Additional Workarounds
+---------------------

Additional mitigations that can be deployed on Cisco devices within
the network are available in the Cisco Applied Intelligence companion
document for this advisory: 
http://www.cisco.com/warp/public/707/cisco-air-20070412-wlc.shtml 

Obtaining Fixed Software
=======================
Cisco has made free software available to address this vulnerability
for affected customers. 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@cisco.com" or "security-alert@cisco.com" 
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@cisco.com 

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 vulnerabilities described in this advisory.

These vulnerabilities were discovered via internal testing and during
the investigation of customer support cases.

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-20070412-wlc.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@cisco.com 
* first-teams@first.org 
* bugtraq@securityfocus.com 
* vulnwatch@vulnwatch.org 
* cisco@spot.colorado.edu 
* cisco-nsp@puck.nether.net 
* full-disclosure@lists.grok.org.uk 
* comp.dcom.sys.cisco@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 |               | Initial    |
| 1.0      | 2007-April-12 | 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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