The amount of counterfeit software infected with malcode has increased significantly since 2006, Microsoft said. A 2006 study by marketing intelligence firm IDC found that 25 percent of counterfeit software tried to install malcode when it was downloaded. Media Surveillance, a German anti-piracy firm, said one of its studies recently found 32 percent of pirated copies of Windows and hacks contained malcode.
Microsoft said the number of complaints it receives annually from people who unknowingly purchased pirated software doubled to 150,000 last year.
The company has begun an anti-piracy campaign in 75 countries called Consumer Action Day.
Microsoft has made available information about counterfeit software and its fight against the problem here.