theranjan writes "When a Security Strategy Director at Microsoft decided to compare Internet Explorer security vulnerabilities with those of Mozilla Firefox, he may have forgotten that the Head Security Strategist of Mozilla was a former MS employee. In a rebuttal of the study, which finds IE more secure than Firefox, Mozilla said that the number of vulnerabilities publicly acknowledged was just a 'small subset' of all vulnerabilities fixed internally. The vulnerabilities found internally are fixed in service packs and major updates without public knowledge. 'For Microsoft this makes sense because these fixes get the benefit of a full test pass which is much more robust for a service pack or major release than it is for a security update. Unfortunately for Microsoft's users this means they have to wait sometimes a year or more to get the benefit of this work. That's a lot of time for an attacker to identify the same issue and exploit it to hurt users.'"