Microsoft has seen a dramatic drop in the number of computers infected with Waledac, a piece of malicious software affiliated with a botnet that was once responsible for a massive amount of spam.
In the second quarter of this year, the company cleaned only 29,816 computers infected with Waledac, down from 83,580 computers in the first quarter of the year. Microsoft published the statistic in its latest biannual Security Intelligence Report released on Wednesday.
The drop in the number of infected machines shows the success of the legal action Microsoft took earlier in the year, said Adrienne Hall, general manager for Microsoft's Trustworthy Computing group.
Waledac was used to send spam and infect computers with fake antivirus software. It used a complicated peer-to-peer system to communicate with other infected machines.
Microsoft's legal moves against Waledac were unprecedented. The company was granted a rare ex parte temporary restraining order (TRO) to shut down malicious domain names that Waledac's controllers used to communicate with infected machines.
Going to court "gives you a blanket way to put on notice that you are going to look into the perpetrators," Hall said.
See : Microsoft Security Intelligence Report (SIR)
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