Cisco patches the wireless LAN controller

Cisco Systems confirms that it has released an update to fix a series of errors that have arisen in the recently discovered wireless LAN controller (WLC). These errors can be exploited to organize a denial of service attack.

The contents of Cisco security warning messages indicate errors arising from a problem in handling the Address Resolution Protocol (ARP) data of WLC control software.

' WLC devices that make mistakes can be mistaken in the process of handling Unicast ARP requests from a wireless workstation, leading to ARP flooding ,' Cisco said.

In other words, when the above situation takes place, there will be two or more WLC units that continuously push a huge amount of ARP requests, flooding the network with unnecessary information flows. The status of hot-spot access points is completely disabled.

Cisco detected the security error from an incident from Duke University (USA). Hot-spot points managed by Cisco were unable to handle large amounts of ARP requests - about 10,000 requests per second.

The device required a connection when it happened that about 150 Apple iPhones were on campus, making it initially thought to be Apple's new product.

However, two days later Duke's Information Technology Director discovered Cisco's hardware failure, not Apple's device. Not only the iPhone, but any other smartphone can be used to create 'ARP storms'.

In its warning message, Cisco listed a total of 3 security bugs but only released a single patch update for WLC version 4.1. Older versions do not yet have an official patch.

Hoang Dung