Microsoft extends security support for Windows XP Microsoft had previously said that it would halt all security updates on 8 April 2014, when support for Windows XP ends. The extension is intended to give organisations a little more time to complete their migrations to newer versions of the operating system, according to Microsoft. Windows XP was the most widely used operating system in the world until August 2012, when Windows 7 overtook it, according to web analytics data generated by Net Applications. As of December 2013, Windows XP market share is still at 28.98 per cent, and many firms have not made sufficient plans to move to a newer system. "The very first month that Microsoft releases security updates for supported versions of Windows, attackers will reverse-engineer those updates, find the vulnerabilities and test Windows XP to see if it shares [them]," wrote Tim Rains, director of Microsoft's Trustworthy Computing group. If it does, attackers will attempt to develop exploit code that can take advantage of those vulnerabilities on Windows XP. Since a security update will never become available for Windows XP to address these vulnerabilities, Windows XP will essentially have a zero-day vulnerability forever. The extended security support applies to Microsoft Security Essentials for consumers and System Center Endpoint Protection, Forefront Client Security, Forefront Endpoint Protection and Windows Intune for enterprise customers. Microsoft said it would continue to work with customers and partners to help them complete their migrations, as Windows XP end of life approaches.