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. This means Rustock is currently responsible for 39 percent of all the world's spam e-mails.
"Overall, the total amount of spam in circulation is down slightly from the previous quarters as most botnets have reduced their number of bots, [but] one exception is Rustock, which has decreased its number of bots, but increased its [spam] volume," according to Paul Wood, a MessageLabs Intelligence senior analyst for Symantec Hosted Services. Rustock has been responsible for a 6-percent increase in spam e-mails per day, he said in a statement.
Read more of "Rustock botnet responsible for 39 percent of all spam" at ZDNet UK.