The Security Intelligence Report emphasized the risks of not upgrading to recent versions of Windows. It found that machines running Windows XP were six times more likely to be infected by malware than machines running Windows 8.
Because Windows XP machines encounter only a third more malware than Windows 8 PCs, it means Windows 8 machines were more likely to repel the malware threat, according to the report.
Microsoft's report found that 21 percent of Microsoft systems are still using Windows XP. Independent reports have put that percentage even higher, with estimates approaching 40 percent in China and many African countries.
The reports also show that the most popular malware attack points are Web-based, via HTML, JavaScript or Java plugin exploits. This is partly due to the success of the Blackhole browser exploit kit, a Web-based threat found in a reported 1.12 percent of computers worldwide in the first quarter of 2013, according to the report.