365 Computer Security Training

Wi-Fi, also called wireless internet or a Wireless Local Area Network (WLAN), has increased the availability of internet access greatly. Unfortunately, it has also introduced new security concerns that are different than the vulnerabilities in wired networks. The standards for Wi-Fi were developed by Institute of Electrical and Electronics Engineers (IEEE) in the early eighties as a set of protocols for wireless computer communication. This set of protocols, named 802.11, is revised periodically to increase speeds and improve security.  Some of the vulnerabilities that have been introduced along with the benefits come from the use of Media Access Control (MAC) address filtering and Wireless Equivalent Privacy (WEP) encryption.

Wireless devices connect to the WLAN network through access points (AP). Nearly all vendors of wireless access point devices, such as Linksys and D-link routers, control access to the network using MAC address filtering. Vulnerabilities are introduced using MAC address filtering because wireless networks may not know all the devices that will attempt to connect to the network. Since MAC address info is sent unencrypted, an attacker can discover the address and impersonate an approved device. Additionally, the complexity and time required to manage a large number of MAC addresses can be cumbersome enough for system administrators to neglect.

WEP encrypts and decrypts communications between devices using a secret key that is known to the AP and the device trying to connect to the network. This method of ensuring confidentially is called shared key authentication. Another less secure method of authenticating devices is called open system authentication, which depends upon verifying that the Service Set Identifier (SSID) of the device matches that of the AP. If an attacker can figure out the SSID of the AP then he will be able to connect to the network.

Shared key authentication methods used by WEP have a relatively short encryption key which means that it can be more easily broken. If an attacker can determine what the secret key is then he can compromise the network. WEP can be cracked in mere minutes using easy to obtain software.