Wardriving is the act of driving in a motorized vehical in an attempt to detect wireless network connections. This is an attempt to find wireless access points. Wardriving is done while using a computer or device equiped with wireless capability that can sense wireless connections that are in range.
An administrator may do wardriving to be sure someone on their network has not connected a wireless access point to their network without permission. If an attacker does wardriving and locates a wireless access point they may try to connect to the network. Some wireless networks are left configured as open and do not even require the remote computer to have a specific media access card (MAC) address to connect. This effectively bypasses the firewall leaving most computer equipment on the network open to direct attack from an attacker.
Leaving wireless access points misconfigured and not having them checked for security is a very serious hazard to the security of any network