Microsoft Teaming Up With FBI, Interpol to Target "Zero Access" Ad Click Bot Net

Says it costs online advertisers $2.7 million a month

Microsoft Corp.'s digital crime unit has teamed up with the U.S. Federal Bureau of Investigation and its European counterpart to fight software that infected more than 2 million computers to steal revenue from online advertisers.

They're working to track down computers that have been taken over with the malicious software known as ZeroAccess or Sirefef, and get rid of the malware, Microsoft said in a statement. While the effort won't eliminate the threat, it should significantly reduce the fraud, which has cost online advertisers an estimated $2.7 million a month, the Redmond, Washington-based company said.