Apple iPhone Air and iPhone 17 Equipped with A19 Chips Featuring Spyware-Resistant Memory Safety
On Tuesday, Apple unveiled a new security feature called Memory Integrity Enforcement (MIE), integrated into its latest iPhone models, including the iPhone 17 and iPhone Air. MIE provides “always-on memory safety protection” across critical attack surfaces, such as the kernel and over 70 userland processes, without compromising device performance. This is achieved through the design of the A19 and A19 Pro chips, which prioritise this aspect. Apple stated that MIE is built on a robust foundation of secure memory allocators, combined with Enhanced Memory Tagging Extension (EMTE) in synchronous mode, and supported by extensive Tag Confidentiality Enforcement policies. The initiative aims to enhance memory safety and thwart malicious actors, particularly those using mercenary spyware, from exploiting vulnerabilities to infiltrate devices through targeted attacks.
The technology behind MIE, EMTE, is an advanced version of the Memory Tagging Extension (MTE) specification released by Arm in 2019, designed to flag memory corruption bugs either synchronously or asynchronously. Notably, Google’s Pixel devices have supported MTE as a developer option since Android 13, while Microsoft has introduced similar memory integrity features in Windows 11. Google Project Zero researcher Mark Brand highlighted that MTE’s ability to detect memory corruption exploitation at the first dangerous access marks a significant improvement in diagnostic and security effectiveness. Apple emphasised that MIE transforms MTE from a “helpful debugging tool” into a revolutionary security feature, protecting against common vulnerabilities like buffer overflows and use-after-free bugs. This involves blocking out-of-bounds requests to access adjacent memory with different tags and retagging memory as it is reused, thereby preventing access to retagged memory with older tags. Apple also noted that Enhanced MTE addresses a key weakness of the original MTE specification by requiring knowledge of a region’s tag to access non-tagged memory from a tagged region, making it considerably more challenging for attackers to exploit out-of-bounds bugs.
Categories: Security Features, Memory Safety, Technology Advancements
Tags: Memory Integrity Enforcement, MIE, iPhone 17, A19 chip, Enhanced Memory Tagging Extension, EMTE, Memory safety, Buffer overflows, Use-after-free bugs, Memory corruption