Waves of widespread, continuous cyber attacks hit the retail sector hard in 2014. Big names, including Home Depot and Michaels, suffered massive data breaches that affected millions of customers. Some experts predicted these hacks would slow in 2015 as new payment systems, such as Apple Pay and credit card chips were introduced. Unfortunately, this simply wasn’t true and this year proved to be no different. Cybercriminals continued their assault on retailers, stealing customer data, including names, addresses, social security numbers and even passport information. With the holiday shopping season in full swing, we took a look at this year to reflect on the retailers who were hit the hardest—and to offer up a few lessons learned.