Your vendors card reader taken over by a rogue credit card. I’ve seen this on tv but never thought it was for real. This is why i constantly tell folks to update EVERYTHING they can…even card readers now are computers running..Linux. However there was a vulnerability in the app for the reader which allowed any firmware update to be installed… without checking for authenticity. Simply swiping a card told the reader to go download a new reader software that not only read the cards but also sent the data to the thieves at this large chain.