Alex talked at BlackHat and Defcon on the subject of Oracle root kits this year. I was thyerre for BlackHat of course as I spoke there myself on the subject of "
unwrapping PL/SQL". Alex's presentation was excellent and went down well with the audience. He started with an overview of what root kits including OS root kits are and also then gave a quick refresher on Oracle root kits part 1. This included how database services / functions and views map to the equivelent OS based features / functions and so on. Then Alex showed how to implement simple root kits and back doors.
Then Alex started on Oracle root kits part2. This was really interesting and covered such things as modifying the Oracle binaries to hide a hacker user in the database. he went on to discuss native compilation and pinned packages.
Alex's presentation slides are titled "Oracle root kits 2.0"