Eavesdropping

Hackers can easily eavesdrop on your network traffic by monitoring the
radio waves transmitted by your access point or wireless router. While
this type of attack is considered passive in nature, it is simple to accomplish.
All the hacker really needs is a radio receiver with a high-gain
antenna that can intercept transmissions of network traffic. This type of
attack can take place without the knowledge of either the network
administrator or the user. For all intents and purposes, there is really
no straightforward defense against this type of attack except to limit the
range of transmission from your wireless access point.
The inherent security that 802.11 offers is by design. Although there
are a number of pieces of equipment on the market designed to intercept
WLAN network traffic, such interception is not easy. 802.11 uses
digital spread spectrum on the 2.4-GHz frequency, meaning its transmission
is spread throughout the band, making it that much harder to
pinpoint the signal and eavesdrop. Moreover, if you enable encryption
on your wireless access point, you are in a better position to resist anyone’s
eavesdropping on your signal because even if a hacker does listen
to your signal, he would have to decode the transmission before making
any usable sense out of it. However, since encryption doesn’t pose much
of an obstacle to a hacker, eavesdropping should be considered a deadly
threat to the safety of any mission-critical information transmitted over
the network.