Malware activity has ramped up in the second quarter of 2017, according to reports from cyber-security firms Cyren, Check Point, Kaspersky Lab, Proofpoint, and Symantec. Ransomware accounted for 68% of all malicious messages containing malware containing malware. Jaff and Locky were heads above everyone else, mainly because these two ransomware families were spread via Necurs, today’s largest spam botnet. Dridex was the most prevalent banking trojan spread via malicious emails.
Source: https://www.bleepingcomputer.com/news/security/ransomware-was-the-most-prevalent-malware-payload-delivered-via-email-in-q2-2017/