CVE-2014-4375

Vulnerability

A double free vulnerability exists in the Mach port handling of Apple iOS prior to version 8 and Apple TV prior to version 7 [1][3]. The bug resides in the kernel's Mach IPC subsystem and can be triggered by a local user manipulating Mach port objects through specific system calls, leading to a use-after-free condition [1][2].

Exploitation

An attacker needs local access to the device and must be able to make specially crafted Mach port system calls [1]. The exploitation sequence involves sending and deallocating Mach port rights in a particular order that causes the kernel to free the same memory region twice [2]. No user interaction beyond running the exploit is required, but the attacker must have already achieved some level of user-level code execution on the device.

Impact

Successful exploitation allows a local attacker to gain elevated privileges within the kernel context, or to cause a denial of service by crashing the device (kernel panic) [1]. The attacker can achieve arbitrary code execution in kernel space, leading to full compromise of the device's security [2].

Mitigation

The vulnerability was fixed in iOS 8 released on September 17, 2014 [1], and in Apple TV 7 released on the same date [3]. Users should update to iOS 8 or later and Apple TV 7 or later to mitigate the issue. No workarounds are available for earlier unpatched versions.