IIRC, the GPU is behind a memory controller, so I doubt corrupting GPU memory alone could lead to an LPE. But I suppose it would give you someplace to store stuff if you can make something else read from it.
Arm published the Memory Tagging Extension (MTE) specification in 2019 as a tool for hardware to help find memory corruption bugs. MTE is a memory tagging and tag-checking system, where every memory allocation is tagged with a secret. The hardware guarantees that later requests to access memory are granted only if the request contains the correct secret. If the secrets don’t match, the app crashes, and the event is logged. This allows developers to identify memory corruption bugs immediately as they occur.
from what they demonstrated, this seems to only be a $100,000 exploit in Apple's bug bounty platform, but if they package it right, it could be a $1.5 million exploit
They simply have to show it against a beta version of MacOS, and frame it as unauthorized access, and maybe from locked mode if possible
unfortunately a little light on the details. I'm very curious how the bug survived through MTE
Upon further reading on data only attacks
(https://www.usenix.org/publications/loginonline/data-only-at...)
This makes more sense. You don't trigger MTE since you're not doing anything for force MTE to take action the program isn't actually changing.
My other question would be, why didn't apple use fbounds checking here? They've been doing it aggressively everywhere else.
MTE plus fbounds checking everywhere should lead to an extremly hardened OS
Quite strange indeed, given that was one of the main points on their security conference a few months ago.
I can only imagine that
1. it’s to performance sensitive
Or
2. The os is so darn large it’s hard to recompile everything
GPU memory/shaders/etc. isn't protected by MTE or PAC. They said "data-only", so I guess GPU commands could fit into this description.
IIRC, the GPU is behind a memory controller, so I doubt corrupting GPU memory alone could lead to an LPE. But I suppose it would give you someplace to store stuff if you can make something else read from it.
Memory Tagging Extension
Arm published the Memory Tagging Extension (MTE) specification in 2019 as a tool for hardware to help find memory corruption bugs. MTE is a memory tagging and tag-checking system, where every memory allocation is tagged with a secret. The hardware guarantees that later requests to access memory are granted only if the request contains the correct secret. If the secrets don’t match, the app crashes, and the event is logged. This allows developers to identify memory corruption bugs immediately as they occur.
https://support.apple.com/guide/security/operating-system-in...
I bought the M5 specifically cause of MIE. Now I feel dumb.
You shouldn’t, MTE blocks a large chunk of vulnerabilities and makes things like rop and jop very difficult if not impossible now.
from what they demonstrated, this seems to only be a $100,000 exploit in Apple's bug bounty platform, but if they package it right, it could be a $1.5 million exploit
They simply have to show it against a beta version of MacOS, and frame it as unauthorized access, and maybe from locked mode if possible
This is an lpe I believe what you’re describing is a zero click rce.
First Mozilla, now even Apple is making up fake vulnerabilities to hype up Mythos. /s
apple didn't "make up" this vulnerability, it was an external team reporting an issue
Cisco put up a totally bogus 10.0 CVE just for this reason, too
Did the article get edited? There is not much description of the field trip.