Windows Server 2003 was supported officially by Microsoft for over 12 years, and it's actually still being used by 0.02 percent of all PCs worldwide, according to info from StatCounter.
Windows server 2003 r2 RSS
A newly discovered security vulnerability in the unsupported Windows Server 2003 R2 operating system is said to be actively exploited by attackers, putting over 60,000 servers using the OS at risk.