In surveying some 80 million domain names, Google has found that nearly half (49 percent) of the world"s malware is coming from only 23 percent of its servers—those being Microsoft"s IIS servers. In Google"s security blog on June 5, an Anti-Malware Team member reported that IIS and Apache (also at 49 percent) evenly split up the malware served, even though Apache makes up almost three times the number of Web servers out there. The remaining 2 percent of malware is served up by "other" servers, Google says.
Overall, Google found that 66 percent of all Web servers examined—not just those serving malware—are Apache servers. IIS servers constitute 23 percent of all servers, nginx accounts for 4 percent and "other" accounts for 7 percent. Netcraft"s May 2007 Web server survey pegs Apache at only 56 percent of the Web servers out there, and Windows at 31.5 percent, out of 118,023,363 sites surveyed.