# XNU XNU is Apple’s hybrid kernel for Darwin-family operating systems, including macOS and iOS. It combines [[Mach]] facilities, BSD-derived process and networking components, I/O Kit driver infrastructure, virtual memory, scheduling, and security-policy enforcement. ## Security position XNU is the operating-system authority beneath ordinary applications and services. Kernel compromise can alter process visibility, memory, networking, security policy, and device-driver behavior, but those claims require evidence at kernel level. ## Evidentiary boundary [[InstallESD.dmg]] modification, [[System Integrity Protection]] bypass, or installation of a privileged daemon can produce durable and powerful effects without modifying XNU. Evidence for XNU involvement would include a kernel exploit chain, altered or unauthorized kernel collections, accepted malicious extensions, kernel-memory artifacts, panic evidence, or verified binary differences. ## Relationships [[Mach]] · [[Linux Kernel]] · [[Kernel Extension]] · [[System Privilege]] · [[Signed System Volume]] · [[Foundational Persistence]]. ## Source [[InstallESD.dmg#What was not established|InstallESD.dmg — what was not established]].