If you are looking for the full installation media (ISO) rather than just the service pack update, the hosts verified community uploads of original retail and volume license discs:
: If you already have Office 2013 installed, using the Microsoft Update service is the recommended way to receive SP1 and subsequent security fixes automatically. Alternative Safe Archival Links If you are looking for the full installation
: Available on Microsoft Support as KB2817430. If you are looking for the full installation