A lot of album art work is missing

Thanks for the info. It looks like my qnap got ransomeware attack this morning (or last night) after research through internet. image ,text files and zip files seems to be the target (pdf.png.jpg etc) and .encrypt extension is added to the files , along with README_FOR_DECRYPT.txtt. I never had this type of attack before, and any guide to fix this would be appreciated.