Hardware Reference
In-Depth Information
In the past, it was thought that the SSID feature provided by the IEEE 802.11 standards was
also a security feature. That's not the case. A Wi-Fi network's SSID is nothing more than a
network name for the wireless network, much the same as workgroups and domains have
network names that identify them. The broadcasting of the SSID can be turned off (when clients
look for networks, they won't immediately see the SSID), which has been thought to provide a
minor security benefit. However, Microsoft has determined that a non-broadcast SSID is
actually a greater security risk than a broadcast SSID, especially with Windows XP and
Windows Server 2003. For details, see “Non-broadcast Wireless Networks with Microsoft
Windows” at
http://technet.microsoft.com/en-us/library/bb726942.aspx
. In fact, many freely
available (and powerful) tools exist that allow snooping individuals to quickly discover your
SSID even if it's not being broadcast, thus allowing them to connect to your unsecured wireless
network.
The only way that the SSID can provide a small measure of security for your wireless network
is if you change the default SSID provided by the wireless access point or router vendor. The
default SSID typically identifies the manufacturer of the device (and sometimes even its model
number). A hacker armed with this information can look up the default password and username
for the router or access point as well as the default network address range by downloading the
documentation from the vendor's website. Using this information, the hacker could compromise
your network if you do not use other security measures, such as WPA/WPA2 encryption. By
using a nonstandard SSID and changing the password used by your router's web-based
configuration program, you make it a little more difficult for hackers to attack your network.
Follow up these changes by enabling the strongest form of encryption that your wireless
network supports.
All Wi-Fi products support at least 40-bit encryption through the wired equivalent privacy (WEP)
specification, but the minimum standard on recent 802.11g products is 64-bit WEP encryption. Many
vendors offer 128-bit or 256-bit encryption on their products. However, the 128-bit and stronger
encryption feature is more common among enterprise products than SOHO-oriented products.
Unfortunately, the WEP specification at any encryption strength has been shown to be notoriously
insecure against determined hacking. Enabling WEP keeps a casual snooper at bay, but someone who
wants to get into your wireless network won't have much trouble breaking WEP. For that reason, all
wireless network products introduced after 2003 incorporate a different security standard known as
Wi-Fi Protected Access (WPA). WPA is derived from the developing IEEE 802.11i security
standard. WPA-enabled hardware works with existing WEP-compliant devices, and software
upgrades are often available for existing devices to make them WPA capable. The latest 802.11g and
802.11n devices also support WPA2, an updated version of WPA that uses a stronger encryption
method. (WPA uses TKIP or AES; WPA2 uses AES.) The new 802.11ac standard does not support
WEP.
Note
Unfortunately, most 802.11b wireless network hardware supports only WEP encryption. The
lack of support for more powerful encryption standards is a good reason to retire your 802.11b
hardware in favor of 802.11g or 802.11n hardware, all of which support WPA or WPA2
encryption.
