voucher_swap: Exploiting MIG reference counting in iOS 12

Posted by Brandon Azad, Project Zero In this post I'll describe how I discovered and exploited CVE-2019-6225, a MIG reference counting vulnerability in XNU's taskswapmachvoucher function. We'll see how to exploit this bug on iOS 12.1.2 to build a fake kernel task port, giving us the ability to re...

iOS/MacOS kernel double free due to IOSurfaceRootUserClient not respecting MIG ownership rules(CVE-2017-13861)

I have previously detailed the lifetime management paradigms in MIG in the writeups for: CVE-2016-7612 https://bugs.chromium.org/p/project-zero/issues/detail?id=926 and CVE-2016-7633 https://bugs.chromium.org/p/project-zero/issues/detail?id=954 If a MIG method returns KERNSUCCESS it means that th...

Apple macOS/iOS - Kernel Double Free due to IOSurfaceRootUserClient not Respecting MIG Ownership Rules

I have previously detailed the lifetime management paradigms in MIG in the writeups for: CVE-2016-7612 https://bugs.chromium.org/p/project-zero/issues/detail?id=926 and CVE-2016-7633 https://bugs.chromium.org/p/project-zero/issues/detail?id=954 If a MIG method returns KERNSUCCESS it means that th...

Apple OS X/iOS Kernel - IOSurface Use-After-Free

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=831 IOSurfaceRootUserClient stores a task struct pointer passed in via IOServiceOpen in the field at +0xf0 without taking a reference. By killing the corrisponding task we can free this pointer leaving the user client with a dangli...