Answer War Chalking
Explanation: War chalking is the technique for presenting the WiFi network publicly. This signifies about the WiFi is present but not describes the manner of it , that is whether it is open connection or closed connection.
It can be used by the people in general as well as hackers . Hackers usually tend to attack and hack its security that is present.Hackers then use the WiFi network is then used for their own work after being hacked.