Shutterfly released the information a week after the breach was discovered. The company is working with law enforcement and a forensics firm to get to the bottom of this incident. They do not know at this time who was behind it and in all likelihood may never learn who the perpetrators were. It appears that Tiny Prints, Treat, and Wedding Paper Divas accounts were using a shared backend infrastructure that was separate from Shutter fly. The only difficulty in this case was not at easy to find on the site at all.”]
Source: https://www.csoonline.com/article/2852901/shutterfly-web-properties-suffer-data-breach.html