Spam on the increase a couple weeks after major spam shutdown

Security researchers who warned the shutdown of McColo Corp. would only lower spam levels for a couple of weeks were correct, as one of the largest botnets on the internet, Srizbi, has been resurrected.

After two ISPs stopped offering service to McColo about two weeks ago, global spam mail dropped 70 percent due to the shutdown. Since last Sunday, spam volume sent rose around 37 percent of the original amount before McColo was pulled offline on November 11.

Srizbi, Asprox, Mega-D, Rustock, and other spam botnets are fully operational again, and in several cases using ISPs located outside of the United States. Any time a botnet is hosted on an ISP not within the United States, it becomes even more difficult to shut down, security experts say.

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