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Memory Integrity Enforcement

(security.apple.com)
458 points circuit | 1 comments | 09 Sep 25 18:25 UTC | HN request time: 0s | source
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tptacek ◴[09 Sep 25 18:51 UTC] No.45186809[source]▶
Both approaches revealed the same conclusion: Memory Integrity Enforcement vastly reduces the exploitation strategies available to attackers. Though memory corruption bugs are usually interchangeable, MIE cut off so many exploit steps at a fundamental level that it was not possible to restore the chains by swapping in new bugs. Even with substantial effort, we could not rebuild any of these chains to work around MIE. The few memory corruption effects that remained are unreliable and don’t give attackers sufficient momentum to successfully exploit these bugs.

This is great, and a bit of a buried lede. Some of the economics of mercenary spyware depend on chains with interchangeable parts, and countermeasures targeting that property directly are interesting.

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leoc ◴[09 Sep 25 20:45 UTC] No.45188753[source]▶
In terms of Apple Kremlinology, should this be seen a step towards full capability-based memory safety like CHERI ( https://en.wikipedia.org/wiki/Capability_Hardware_Enhanced_R... ) or more as Apple signaling that it thinks it can get by without something like CHERI?
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pizlonator ◴[09 Sep 25 21:21 UTC] No.45189370[source]▶
MTE and CHERI are so different that it’s hard and maybe not even possible to do both at the same time (you might not have enough spare bits in a CHERI 128 bit ptr for the MTE tag)

They also imply a very different system architecture.

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quotemstr ◴[09 Sep 25 21:25 UTC] No.45189425[source]▶
> MTE and CHERI are so different that it’s hard and maybe not even possible to do both at the same time (you might not have enough spare bits in a CHERI 128 bit ptr for the MTE tag)

Why would you need MTE if you have CHERI?

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pizlonator ◴[09 Sep 25 21:29 UTC] No.45189480[source]▶
Not saying you’d want both. Just answering why MTE isn’t a path to CHERI

But here’s a reason to do both: CHERI’s UAF story isn’t great. Adding MTE means you get a probabilistic story at least

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1. quotemstr ◴[09 Sep 25 21:32 UTC] No.45189519{5}[source]▶
Some progress on UAF though! https://dl.acm.org/doi/10.1145/3703595.3705878