A skimmer is a tiny electronic device that a criminal physically hacks into a payment card reader. It’s created to be installed instantly (in less than 60 seconds) so that the criminal can get in, make the change, and get out without raising doubts.
It’s nearly impossible to detect a skimmer ar gas pump, that’s because crooks will usually open the pump with a master key and place the skimmer inside the pump. There usually aren’t any clues on the outside that would clue you into the skimmer’s residence except the Bluetooth signal that crooks use to stealthily obtain stolen card data.
Most gas pump skimmers broadcast their presence using the HC-05 identifier and use the default password of “1234.” Moreover, the most popular version of the software that runs on these devices answers with the letter “M” every time a user sends a query of “P”.
According to the app description:
Fuel Pump Skimmers can steal your Credit or Debit Card information without you ever suspecting. This app uses your phone’s Bluetooth radio to detect a common radio component in modern fuel pump skimmers (HC-05) and warn you if you’re about to get scammed.