Your inbox might feel a little empty for a while because Microsoft and the Feds have taken down the world’s largest botnet, “Rustock,” estimated to have infected over 1 million computers worldwide.

A botnet is a series of computers infected with code that lets them be controlled remotely, often for the sending of spam.

The raid, conducted last Wednesday, had Microsoft’s digital crimes unit, accompanied by U.S. Marshals, entering 7 different server facilities and seizing the master computers alleged to be sending the command instructions to the infected machines.

Symantec reported in a blog post that in the day after the Rustock takedown, worldwide spam levels dropped by 12%.

In an interesting twist, Microsoft was able to target and seize the machines by saying the botnet was infringing on its trademarks by sending out fake Microsoft lottery emails.

Botnets typically exploit vulnerabilities in Windows browsers and operating systems, which dominate market share, to distribute spam and infect other computers.

Read the lawsuit here. (PDF)
Spam Network Shut Down [WSJ]
Taking Down Botnets: Microsoft and the Rustock Botnet [Microsoft on the Issues]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.