The vast majority of intrusion into business networks happens within a malicious email that your email filters did not catch. As edge security to networks grows tighter, malicious practices have turned aggressively towards targeting company employees with malicious code and programs attached to emails. Trend Micro outlines some great stories we can all learn from and understand why robust email security is now more important than ever. https://www.trendmicro.com/vinfo/us/security/news/business-email-compromise