Rustock botnet responsible for 39 percent of all spam

Botnets are now responsible for sending 95 percent of all spam, up from 84 percent in April, and almost half of that spam comes from a single botnet, Rustock.

Rustock sent 41 percent of the world's botnet spam in August, up from 32 percent in April. This is despite the network actually shrinking in size from 2.5 million to 1.3 million bots over the same period, security company Symantec said on Tuesday.