Wardriving
This is an internal reconnaissance technique used specifically for surveying wireless networks and is commonly done from an automobile. It is targeted mostly at unsecured Wi-Fi networks. There are a few tools that have been made for the purpose of wardriving, and the two most common are network stumbler and mini stumbler. Network stumbler is Windows-based and it records SSIDs of unsecured wireless networks before using GPS satellites to record the exact location of the wireless network. The data is used to create a map used by other wardrivers to find unsecured or inadequately-secured wireless networks. They can then exploit the network and its devices since entrance is free.
Mini stumbler is a related tool, but has been designed to run on tablets and smartphones. This makes wardrivers look less suspicious when identifying or exploiting a network. The functionality of the tool will simply find an unsecured network and record it in an online database. Wardrivers can then come later on to exploit the network using a simplified map of all the identified networks. As for Linux, there is a tool called Kismet that can be used for wardriving.
The tool is said to be very powerful as it lists unsecured networks and details of the clients on networks such as BSSIDs, signal levels, and IP addresses. It can also list the identified networks on maps, allowing attackers to come back and attack the network using the known information. Primarily, the tool sniffs the 802.11 layer 2 traffic of a Wi-Fi network and uses any Wi-Fi adapter on the machine it has been installed in (1).