Hiding Data In Hard-Drive's Service Areas

In this paper the author demonstrates how spinning hard-drives' service areas can be used to hide data from the operating-system (or any software using the standard OS's API or the standard ATA commands to access the hard-drive). These reserved areas are used by hard-drive vendors to store modules that in turn operate the drive, and in a sense, together with the ROM, serve as the hard-drive’s internal storage and OS. By sending Vendor Specific Commands (VSCs) directly to the hard-drive, one can manipulate these areas to read and write data that are otherwise inaccessible. This should not be confused with DCO or HPA which can be easily detected, removed and accessed via standard ATA commands.