According to a report in the Financial Times, Google are phasing out the use of Microsoft's Windows within the company because of security concerns. Citing several Google employees, the FT report reports that new hires are offered the option of using Apple Mac systems or PCs running Linux. The move is believed to be related to a directive issued after Google's Chinese operations were attacked in January. In that attack, Chinese hackers took advantage of vulnerabilities in Internet Explorer on a Windows PC used by a Google employee and from there gained deeper access to Google's single sign on service.
Google are also encouraging employees to use Google's own products such as Chrome and ChromeOS internally as part of the initiative and hopes that with these steps it can isolate employees from common Windows pests such as viruses and malware. For Mac OS X and Linux there are virtually no equivalent pests. However, the Mac OS X and Linux developers are not infallible and there are weaknesses in these systems which could be used to create exploits. The change will probably protect Google employees from un-targeted attacks that just require a user to visit a web page, but they may be less likely to protect against targeted attacks where the attacker usually has sophisticated exploits available. For example, at the Pwn2Own competition earlier this year, hacker Charlie Miller showed how quickly the Safari browser on Mac OS X could be cracked using an unknown vulnerability.