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Modern iOS Security Features – A Deep Dive into SPTM, TXM, and Exclaves

Modern iOS Security Features – A Deep Dive into SPTM, TXM, and Exclaves

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·October 13, 2025
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Moral_

SEAR and the Apple team does an excellent job of security on iOS, and should be commended greatly on that.

Not only are they willing to develop hardware features and plumb that throughout the entire stack, they're willing to look at ITW exploits and work on ways to mitigate that. PPL was super interesting, they decided it wasn't 100% effective so they ditched it and came up with other thigs.

Apple's vertical makes it 'easy' to do this compared to Android where they have to convince the CPU guys at QC or Mediatek to build a feature, convince the linux kernel to take it, get it in AOSP, get it in upstream LLVM, etc etc.

Pointer authentication codes (PAC) is a good example, Apple said f-it we'll do it ourselves. They maintained a downstream fork of LLVM, and built full support, leveraged in the wild bypasses and fixed those up.

dagmx

One of the knock on benefits of this too is increased security across all platforms as long as someone exercises that code path on one of apples new processors with a hardened runtime.

In theory it makes it easier to catch stuff that you can’t simply catch with static analysis and it gives you some level of insight beyond simply crashing.