It's really not that easy for someone to do it. The problem is getting someone to give you a connection that can actually put that many packets onto the Internet. Even the author has issues with this points. See http://blog.erratasec.com/2013/09/masscan-entire-internet-in...

> The problem is that I don't have a 10-gbps network to test on. My ISP let's me go out to 100,000 packets/second as long as I deal with the abuse complaints, but that's around 44-mbps.