Cracking of Wireless Networks - Prevention

Prevention

An unprotected wireless network is extremely insecure. From anywhere within broadcast range, someone can eavesdrop or start using the network. Therefore, the IEEE 802.11 standard for wireless networks was accompanied with Wired Equivalent Privacy (WEP). This security protocol takes care of the following:

• authentication: assurance that all participants are who they state they are, and are authorized to use the network
• confidentiality: protection against eavesdropping
• integrity: assurance of data being unaltered

WEP has been criticized by security experts. Most experts regard it as ineffective by now.

In 2004 a draft for a better security protocol appeared, and it was included in the IEEE 802.11 standard in 2007. This new protocol, WPA2, uses an AES block cipher instead of the RC4 algorithm and has better procedures for authentication and key distribution. WPA2 is much more secure than WEP, but WEP was still in wide use in 2009.

Many wireless routers also support controlling the MAC addresses of computers that are authorized to use a wireless network. This measure can effectively stop a neighbour from using the network, but experienced intruders will not be stopped. MAC filtering can be attacked because a MAC address can be faked easily.

In the past, turning off the broadcasting of the SSID has also been thought to give security to a wireless network. This is not the case however. Freely available tools exist that quickly discover an SSID that is not broadcast. Microsoft has also determined that switching off the broadcasting of the SSID leads to less security. Details can be found in Non-broadcast Wireless Networks with Microsoft Windows.

Returning to encryption, the WEP specification at any encryption strength is unable to stand determined hacking. Therefore, Wi-Fi Protected Access (WPA) was derived from WEP. Software upgrades are often available. The latest devices that conform to the 802.11g or 802.11n standards also support WPA2. (WPA uses the TKIP encryption, WPA2 uses the stronger AES method.) It is recommended to use only hardware that supports WPA or WPA2.