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Cisco Wireless LAN Controllers Denial of Service Vulnerability

Advisory ID: cisco-sa-20110427-wlc

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110427-wlc

Revision 1.0

For Public Release 2011 April 27 16:00  UTC (GMT)


Summary

The Cisco Wireless LAN Controller (WLC) product family is affected by a denial of service (DoS) vulnerability where an unauthenticated attacker could cause a device reload by sending a series of ICMP packets.

Cisco has released free software updates that address this vulnerability.

There are no available workarounds to mitigate this vulnerability.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110427-wlc.

Affected Products

Vulnerable Products

This vulnerability affects Cisco WLC software versions 6.0 and later. The following products are affected by the vulnerability described in this Security Advisory:

Determination of Software Versions

Administrators can use these instructions to determine the software version that is running on a Cisco WLC using the web or command-line interface or on a Cisco WiSM (using commands on a Cisco Catalyst 6500 Series Switch and Cisco 7600 Series Router).

Cisco Wireless Controllers

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

  • In the web interface, choose the Monitor tab, click Summary in the left pane, and note the Software Version field.

    Note: Customers who use a Cisco WLC Module in an ISR will need to issue the service-module wlan-controller <slot/port> session command prior to performing the next step on the command line. Customers who use a Cisco Catalyst 3750G Switch with an integrated WLC Module will need to issue the session <Stack-Member-Number> processor 1 session command prior to performing the next step on the command line.

  • From the command-line interface, type show sysinfo and note the Product Version field, as shown in this example:
    (Cisco Controller)> show sysinfo
    
    Manufacturer's Name.. Cisco Systems Inc.
    Product Name......... Cisco Controller
    Product Version...... 5.1.151.0
    RTOS Version......... Linux-2.6.10_mvl401
    Bootloader Version... 4.0.207.0
    Build Type........... DATA + WPS
    <output suppressed>

Cisco WiSMs

Use the show wism module <module number> controller 1 status command on Cisco Catalyst 6500 Series Switch and Cisco 7600 Series Routers that have a WiSM installed. Note the software version as demonstrated in this example, which shows version 5.1.151.0:

Router# show wism module 3 controller 1 status

WiSM Controller 1 in Slot 3
Operational Status of the Controller    
   : Oper-Up
Service VLAN                            
   : 192   
Service Port                            
   : 10    
Service Port Mac Address                
   : 0011.92ff.8742
Service IP Address                      
   : 192.168.10.1
Management IP Address                   
   : 192.168.1.123
Software Version                        
   : 5.1.151.0
Port Channel Number                     
   : 288   
Allowed vlan list                       
   : 30,40 
Native VLAN ID                          
   : 40    
WCP Keep Alive Missed                   
   : 0

Products Confirmed Not Vulnerable

The following Cisco Wireless LAN Controllers are not affected by this vulnerability:
  • Cisco 2000 Series WLCs
  • Cisco 2500 Series WLCs
  • Cisco 4100 Series WLCs
  • Cisco 4400 Series WLCs
  • Cisco Catalyst 3750G Integrated WLCs
  • Cisco 5500 Series WLCs
  • Cisco Wireless Services Modules (WiSMs, both WiSM and WiSM2)
  • Cisco Wireless Services Ready Engine (SRE) Modules
  • Cisco Flex 7500 Series Cloud Controllers
No other Cisco products are currently known to be affected by these vulnerability.

Details

Cisco WLCs and Cisco WiSMs are responsible for system-wide wireless LAN functions, such as security policies, intrusion prevention, RF management, quality of service (QoS), and mobility.

These devices communicate with controller-based access points over any Layer 2 (Ethernet) or Layer 3 (IP) infrastructure using the Lightweight Access Point Protocol (LWAPP) and the Control and Provisioning of Wireless Access Points (CAPWAP) protocol.

The Cisco WLC family of devices is affected by a DoS vulnerability that can allow an unauthenticated attacker to cause the device to reload by sending a series of ICMP packets. This vulnerability can be exploited from both wired and wireless segments.

This vulnerability is documented in Cisco bug ID  CSCth74426 (  registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-1613.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

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

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

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 .

CSCth74426 - Certain ICMP traffic could cause WLC to crash

Calculate the environmental score of CSCth74426

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed


Impact

Successful exploitation of this vulnerability could cause an affected device to reload. Repeated exploitation could result in a sustained DoS condition.

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.

If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. 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.

Affected Release

First Fixed Release

4.0

Not Vulnerable

4.1

Not Vulnerable

4.1 M

Not Vulnerable

4.2

Not Vulnerable

4.2M

Not Vulnerable

5.0

Not Vulnerable

5.1

Not Vulnerable

5.2

Not Vulnerable

6.0

6.0.200.0

7.0

7.0.98.216 and 7.0.112.0


Workarounds

There are no available workarounds to mitigate this vulnerability.

Obtaining Fixed Software

Cisco has released free software updates that address these vulnerabilities. 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/en/US/docs/general/warranty/English/EU1KEN_.html , or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml .

Do not contact 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 agreements 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 do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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

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

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including 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.

This vulnerability was found during internal testing.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110427-wlc

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 1.0

2011-April-27

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/web/about/security/psirt/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.