Phantasmagoria hides tasks without modifying syscalls in Linux kernel v2.4. Includes a paper “Smashing The Kernel For Fun And Profit” and proof of concept code.
You can download it from the following link: https://packetstormsecurity.com/files/download/29569/Phantasmagoria.tgz
Source: https://packetstormsecurity.com/files/29569/Phantasmagoria.tgz.html