Memory Integrity Enforcement

Memory Integrity Enforcement (MIE) is the culmination of an unprecedented design and engineering effort, spanning half a decade, that combines the unique strengths of Apple silicon hardware with our advanced operating system security to provide industry-first, always-on memory safety protection across our devices — without compromising our best-in-class device performance. We believe Memory Integrity Enforcement represents the most significant upgrade to memory safety in the history of consumer operating systems.

→ security.apple.com/blog/memory-integrity-enforcement/

Apple introduced Memory Integrity Enforcement (MIE) as a new memory safety feature for iPhone 17 and iPhone Air devices. MIE combines Apple silicon hardware with operating system security to block memory corruption attacks.

It works always and protects key areas like the kernel without slowing down the device. Apple spent five years on this design. No common malware has ever attacked iPhone at the system level. Only rare spyware from state actors uses memory bugs. These bugs let attackers change data or take control.

Apple fights this with safe tools like the Swift language. They also built secure memory allocators called kalloc_type and xzone malloc. In 2018, Apple added Pointer Authentication Codes (PAC) to chips. This stops attacks on code flow. Then Apple looked at Arm's Memory Tagging Extension (MTE). MTE tags memory to find errors. Apple worked with Arm to improve it into Enhanced Memory Tagging Extension (EMTE).

EMTE checks tags in real time to block bad access. MIE uses secure allocators plus EMTE to stop buffer overflows and use-after-free bugs. It tags small memory blocks that allocators miss. MIE also guards non-tagged memory and fights attacks from wrong guesses in the chip.

Apple put extra chip space and speed into MIE for strong protection. Tests show MIE stops real spyware chains early. Apple lets developers test MIE with Xcode's Enhanced Security setting. MIE makes attacks much harder and costlier. It changes memory safety for consumer devices forever.