Largest internet census by a botnet

In 2012 an anonymous hacker conducted an illegal census of the internet by creating and releasing the Carna Botnet. It was able to infiltrate around 420,000 devices globally that had no passwords or default passwords and then used these devices to map out the internet. The botnet client itself was 60 kb in size and operated between March and December 2012, gathering some 9 TB of data.