The award, by the National Information Assurance Partnership, gives the operating system Evaluation Assurance Level (EAL) 4 certification, which makes it more applicable for some government organisations making buying decisions.
Although the original ‘out-of-the-box’ Windows installation wasn't certified, 20 specific configurations of ‘real-world scenarios’ were rated.
Level 4 is the usual level for commonly used software with commercial applications, such as an operating system, Microsoft said, though the highest level of Common Criteria certification is 7, which normally applies to specialised security engineering techniques.
Last year, the US Air Force struck a unique deal with Microsoft for a specially configured version of Windows to be used by all its 525,000 personnel and civilian support staff. Fed up with security problems, the department demanded – and got – a single version of Microsoft products, built with extra security, to help it apply software patches whenever Microsoft announces new vulnerabilities.