According to Microsoft’s latest Security Intelligence Report, released today, Windows Vista (Service pack 1) is 61.9 percent less likely to be infected by malware than Windows XP (Service Pack 3).
The biennial report covers the first half of 2009 and most of the current Microsoft operating system, but not Windows 7.
The report states that the Conficker worm continued to be the most prevalent mlware for the fist half of 2009, infecting more than 5,000,000 PCs. Conficker spreads either by exploiting vulnerable Microsoft Windows Servers, through infected USB or thumb drives or by brute-forcing weak passwords on PCs. (see Common Strategies for Securing your PC)
The data is collected from Windows Defender, the Malicious Software Removal Tool (MRT) and Security Essentials.