Microsoft this week issued a study that examines the malicious software threat to Windows computers … a report clearly written from the software giant’s vantage point. While the report includes some interesting stats about which malware samples were most prevalent on customer machines last year, the most meaningful section of the report focuses on a new development that may force Microsoft to redefine its approach to security. Microsoft said the number of security bulletins it released in 2007 was 11.5 percent lower than in 2006, and that the number of vulnerabilities covered by those bulletins was 29.6 percent lower than the number covered by the 2006 bulletin (the term “bulletin” is a bit of an artificial construction that does not equate to the total number of vulnerabilities, because Microsoft’s “bulletins” often fix multiple security flaws). If Microsoft issued fewer patches last year, attackers hardly noticed. In 2007, instructions for exploiting