Hooked on Linux: Rootkit Taxonomy, Hooking Techniques and Tradecraft
Elastic Security Labs publishes a comprehensive two-part research series on Linux rootkit taxonomy, evolution, and hooking techniques. Part one traces rootkit development from early 2000s userland LD_PRELOAD techniques through LKM-based syscall hooking, eBPF-based in-kernel bytecode injection, and emerging io_uring-based evasion methods. The article details loader and payload components, hooking primitives (IDT, syscall table, ftrace, LSM hooks), and real-world examples including Diamorphine, Reptile, Triple Cross, Boopkit, and RingReaper.