A computer-implemented method includes: monitoring, by a computing device, outputs of sensors associated with a machine that receives magnetic stripe cards; in response to the monitoring, detecting, by the computing device, the output of at least one of the sensors indicates an event; in response to the detecting the event, determining, by the computing device, a number of the sensors whose output indicates a respective event during a predefined time period; selecting, by the computing device, a security action from a plurality of predefined security actions based on the determined number of the sensors whose output indicates a respective event during the predefined time period; and initiating, by the computing device, the security action.