Microsoft has been granted a license to kill by a federal judge, allowing it to take down the massive Waledac botnet.
"This legal and industry operation against Waledac is the first of its kind, but it won’t be the last," says the company's general counsel Tim Cranton.
One of the largest botnets in the US, Waledac is believed to have infected hundreds of computers woeldwide, and to have had the capacity to send over 1.5 billion spam emails a day.
Microsoft says that during a three-week period in December last year, around 651 million spam emails from Waledac went to Hotmail accounts alone, including offers and scams related to online pharmacies, imitation goods, jobs, penny stocks and more.
Earlier this week, a federal judge at the US District Court of Eastern Virginia granted a temporary restraining order cutting off 277 Internet domains believed to be run by criminals as the Waledac bot.
"This action has quickly and effectively cut off traffic to Waledac at the '.com' or domain registry level, severing the connection between the command and control centers of the botnet and most of its thousands of zombie computers around the world," says Cranton.
"Three days into the effort, Operation b49 has effectively shut down connections to the vast majority of Waledac-infected computers, and our goal is to make that disruption permanent."