The Rustock botnet, which was taken down in March, had been sending as many as 13.82 billion spam emails daily, accounting for an average of 28.5 percent of global spam sent from all botnets during the month, according to a new report from Symantec.

Symantec has released its April 2010 MessageLabs Intelligence report, which found that Rustock has surpassed Cutwail as the biggest botnet both in terms of the amount of spam it sends and the amount of active bots under it control. While Rustock has reduced the output of individual bots by 65 percent, it has increased the [...]