Cisco Wireless LAN Controller contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available.
A vulnerability in the WebAuth feature of Cisco Wireless LAN Controllers (WLC) could allow an unauthenticated, remote attacker to cause the device to reload.
The vulnerability is due to a failure to deallocate memory used during the processing of a WebAuth login. An attacker could exploit this vulnerability by creating a large number of WebAuth requests at a high rate and leave them in an uncompleted state. An exploit could allow the attacker to consume all available memory on the device. This causes a watchdog process to restart the WLC, resulting in a denial of service (DoS) while the device reboots.
The WebAuth feature must be enabled and configured for a device to be affected by this vulnerability. This feature is disabled by default.
Cisco has confirmed the vulnerability in a security advisory and release software updates.
Cisco Wireless LAN Controller software versions prior to 220.127.116.11 and 18.104.22.168 are affected.
Only devices with WebAuth enabled could be targeted for exploitation. The WebAuth feature is disabled by default, reducing the potential number of vulnerable devices.
Attackers may require access to internal networks to send authentication requests to a vulnerable device, limiting the source of exploitation.
An unauthenticated, remote attacker could exploit this vulnerability to consume available memory and cause the device to restart, resulting in a DoS condition.
The vulnerability is due to improper processing of WebAuth login attempts by the affected device software.
An unauthenticated, remote attacker could exploit this vulnerability by sending a continuous series of authentication attempts to the vulnerable device. The processing of the login attempts could cause the device to consume increasing amounts of memory. The exhaustion of available memory could cause the device to restart, resulting in a DoS condition.
Administrators are advised to apply the appropriate 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 affected systems.
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 email at firstname.lastname@example.org.
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