Last month, Check Point researchers were able to spot the distribution of Jaff Ransomware by the Necurs Botnet. The ransomware was spread using malicious PDF files that had an embedded docm file, which in its turn downloaded an encoded executable. After the downloaded file was decoded, the ransomware encrypted the user’s files. In the last weeks, however, we were able to detect a new spam campaign delivering the ransomware and altering the chain of infection to use malicious WSF files.

http://blog.checkpoint.com/2017/06/08/jaff-ransomware/