Despite the shutdowns of several spam friendly ISPs, the number of botnets sending out spam has increased. The newest kid on the block is the Maazben botnet, which was first discovered in May.  It joins veteran botnet Rustock in spewing out millions of online casino spams each day. Rustock is responsible for 10% of all spam sent, while Maazben is responsible for 1.4%. That doesn’t seem like much but that volume has doubled since August.

While the monster botnet Cutwai, responsible for nearly 46% of all spam sent at its peak, was severely crippled by an ISP shut down, botnets Grum and Bobax have quickly jumped in to make up for it, and together are responsible for 39% of all spam sent.

Botnets are also beginning to be used for more than just spewing spam and stealing passwords.  The Gumblar botnet infects websites and uses them to distribute malware, and the Bahama botnet uses the computers it infects to commit click fraud. What’s more, the sheer number of botnets around now has made DDoS attacks easier and cheaper than ever. While such attacks don’t result in profits, they are still used to muzzle critics, knock online competitors out, and otherwise send an unpleasant message to an individual or group.

Botnets are here to stay. They are growing more sophisticated and powerful everyday and it is going to be more and more difficult to stay ahead of them.