Cisco Security Advisory
Cisco Airespace Wireless LAN Controllers Allow Unencrypted Network Access
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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 https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20051102-lwapp.
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This section provides details on 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
These products are not vulnerable:
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Access points other than Cisco 1200, 1131 and 1240 series are not
affected.
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Access points that are deployed without a separate WLAN controller
are not affected.
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Access points that are controlled by WLAN controllers other than
Cisco 2000 and 4400 series are not affected.
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Access points that are controlled by WLAN controllers which are
running a software version other than 3.1.59.24 are not affected.
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Access points that are running in autonomous mode are not
affected.
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Access points that are running VxWorks are not affected.
No other Cisco products are currently known to be affected by these vulnerabilities.
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Access points other than Cisco 1200, 1131 and 1240 series are not
affected.
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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 IOSŪ. 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/products/ps6306/prod_white_papers_list.html
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 ( registered customers only) .
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There are no workarounds for this issue.
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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.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Revision 1.0
2005-Nov-2
Initial public release
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