Cisco has released an updated security advisory to identify additional software versions affected by the Cisco Wireless LAN Controller denial of service vulnerability.
Cisco Wireless LAN Controller software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to errors in processing malformed network packets. An unauthenticated, remote attacker could exploit this vulnerability by sending malicious network requests to the targeted device. A successful exploit could cause the device to reload, resulting in a DoS condition.
Cisco has confirmed this vulnerability and has released updated software.
Devices that are running the following versions of Cisco Wireless LAN Controller software are vulnerable:
Versions prior to 184.108.40.206
All 4.1 versions
All 4.1M versions
Versions prior to 220.127.116.11
Versions prior to 18.104.22.168M
All 5.0 versions
All 5.1 versions
Versions prior to 22.214.171.124
Versions prior to 126.96.36.199
Attackers may require access to trusted, internal networks to be able to send malicious IKE packets over wired networks to the targeted device. The attacker could also exploit the vulnerability over wireless networks, but the attacker must gain physical proximity to the device to access it via a wireless connection.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
An unauthenticated, remote attacker could exploit this vulnerability to cause a device to reload, resulting in a DoS condition.
The vulnerability is due to errors in processing Internet Key Exchange (IKE) network packets. Devices accept IKE packets on both wired and wireless networks as part of authentication routines.
An unauthenticated, remote attacker could exploit this vulnerability by sending a malicious network packet to the device. When processed, the packet could cause the device to reload, resulting in a DoS condition.
Administrators are advised to apply the available software updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor critical systems.
The Cisco Applied Intelligence team has created the following companion document to guide administrators in identifying and mitigating attempts to exploit this vulnerability prior to applying updated software: cisco-amb-20100908-wlc
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at email@example.com.
Version 1, September 8, 2010, 12:07 PM: Cisco Wireless LAN Controller software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
The urgency and severity ratings of this alert are not tailored to individual users; users may value alerts differently based upon their network configurations and circumstances. THE ALERT, AND INFORMATION CONTAINED THEREIN, ARE PROVIDED ON AN "AS IS" BASIS AND DO NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE ALERT, AND INFORMATION CONTAINED THEREIN, OR MATERIALS LINKED FROM THE ALERT, IS AT YOUR OWN RISK. INFORMATION IN THIS ALERT AND ANY RELATED COMMUNICATIONS IS BASED ON OUR KNOWLEDGE AT THE TIME OF PUBLICATION AND IS SUBJECT TO CHANGE WITHOUT NOTICE. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE ALERTS AT ANY TIME.