In a very bold statement, Microsoft has claimed that 1 in 14 downloads made are somewhat malicious, and that five percent of users ignore browser warnings and proceed to download malware anyway. These facts have been highlighted in a recent report by Microsoft that states how great their SmartScreen browser defense is, which claims to have blocked 1.5 billion website-based malware installs since the release of IE8.
The SmartScreen filter, which was expanded in IE9 to warn users of potentially dangerous applications, apparently has between a 25-70% success rate at identifying 0-day malware. This filter, despite having a fairly high false-positive rate, doesn't warn users for 90% of program downloads.
These numbers, especially the 1/14 downloads and 1.5 billion blocked malware installs, seem unusually high, the latter of which indicates that 75% of all Internet users in the world have been saved from a malware install by IE8+ at least once. According to NetMarketShare, 35% of browsers in April 2011 were either IE8 or IE9, which makes the 1.5 billion blocks jump to two attempted malware installs per IE8/9 user.
Now let’s take that number even further. Microsoft claims that one in 14 downloads are malicious; this means that, as IE8/9 users download one piece of malware each per year (whether they choose to or not), those users only download 14 files per year when you assume IE8/9 successfully blocks all attempts. This number is even less when you factor in that just 25-70% of malware IE identifies is actually malware (~7 downloads in total per year per user).
These numbers just seem too high to be correct, which could indicate upwards of 3 billion attempted malware installs per year over every browser. This means that one in two humans living on Earth, regardless of whether they actually have an internet connection or not, attempt to (unwillingly) infect their computer with one malware every year. Microsoft, something isn't quite right.