Moore’s census involved regularly sending simple, automated messages to each one of the 3.7 billion IP addresses assigned to devices connected to the Internet around the world (Google, in contrast, collects information offered publicly by websites). Many of the two terabytes (2,000 gigabytes) worth of replies Moore received from 310 million IPs indicated that they came from devices vulnerable to well-known flaws, or configured in a way that could to let anyone take control of them.

via Pinging the Whole Internet Reveals Unsecured Backdoors That Could Tempt Hackers and Cyber Criminals | MIT Technology Review.