System Integrity Protection (SIP)

Introduction to Apple System Integrity Protection on macOS

This article explores the workings, components, security implications, and management of System Integrity Protection. It builds upon the previous article, as SIP is the default Sandbox Profile used for all macOS apps:

Snake&Apple VIII — App Sandbox

In Unix-based systems, the root user traditionally has unrestricted access to all files and processes. Such privilege allows powerful operations but also presents security risks. Malware with root privileges can manipulate files and make harmful changes. Before SIP, macOS followed this model, and malware with root access could cause significant damage.

Dear Reader, if you missed the above article and Sandbox on macOS is black magic to you, I recommend reading it first — especially about Sandbox Profiles.

Overview

System Integrity Protection is a component that helps protect MacOS from malicious software and mitigates its effects once the system is infected.

• It prevents altering essential system files and directories.
• It restricts the root user (and others) from performing sensitive actions.

These sensitive actions are untrusted kext loading, obtaining task ports on system processes using task_for_pid or debugging/tracing them, kernel debugging, modifying NVRAM, overriding executable policy, and modifying RecoveryOS.

This way, SIP ensures that system software remains trusted. Malware, even with root privileges, cannot tamper with system integrity.

For reference, check: About System Integrity Protection on your Mac.

Platform Profile

SIP is also called a Platform Profile because it is a system-wide setting that is on by default and applied to every process running on the system, regardless of whether it runs sandboxed or with root access.