In the first three months after shipping the Windows Defender Beta 2 anti-spyware application, Microsoft detected 22 million pieces of adware/spyware programs in Windows machines, resulting in about 14 million removals.
According to statistics released by the Redmond, Wash., company, more than 60 percent of Windows Defender users have opted to remove the ad-serving programs when offered a choice.
In a detailed report released Oct. 24 at RSA Conference Europe in Nice, France, Microsoft offered the first glimpse of the extent of the adware/spyware threat on Windows machines, using detection and removal data from Windows Defender and the Windows Live OneCare safety scanner, two freely available tools.
During the period from April 11 to June 30, Windows Defender removed 2,849 unique families of "potentially unwanted software," the report said. Those programs include adware, spyware, Trojan downloaders, setting modifiers and P2P (peer-to-peer) software bundlers.
The top 25 most-removed programs include Direct Revenues ABetter-Internet.DrPMon, Total Velocitys TV Media Display, Twain Techs browser add-on for Internet Explorer, WhenUs SaveNow adware program, Zango SearchAssistant, and the Kazaa and BearShare file-sharing applications.
However, Microsoft cautions in the report that the data does not take into account whether the adware/spyware was installed by itself or as part of a bundle, whether installation was consensual, or whether a program was installed by the primary operator of the computer. "Because these variables are not included, one must be careful not to draw unwarranted conclusions from the data," the report said.
The data culled from the Web-based Windows Live OneCare scanner—which also detects and removes spyware—shows slightly different results, primarily because users are actively looking to remove a potential threat.
On the Windows Live OneCare scanner, WhenUs SaveNow program was the most-removed program, followed by NewDotNet, Kazaa, Claria, Hotbar and Zango SearchAssistant.
The Windows Defender tool, which was born out of Microsofts December 2004 acquisition of Giant Company Software, counts more than 14 million active customers.