CVE-2014-4495 in iOS
Summary
by MITRE
The kernel in Apple iOS before 8.1.3, Apple OS X before 10.10.2, and Apple TV before 7.0.3 does not enforce the read-only attribute of a shared memory segment during use of a custom cache mode, which allows attackers to bypass intended access restrictions via a crafted app.
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Analysis
by VulDB Data Team • 12/15/2024
This vulnerability resides in the kernel implementation of Apple's operating systems affecting iOS versions before 8.1.3, OS X versions before 10.10.2, and Apple TV versions before 7.0.3. The flaw manifests in the memory management subsystem where the kernel fails to properly enforce memory protection mechanisms during shared memory operations. Specifically, when applications utilize custom cache modes for shared memory segments, the system does not adequately verify that these segments are marked as read-only, creating a privilege escalation vector that undermines the fundamental security model of memory isolation.
The technical root cause involves improper validation of memory protection attributes within the kernel's shared memory management routines. When a custom cache mode is employed, the kernel should enforce strict access controls based on the segment's declared attributes including read-only status. However, the implementation contains a logic flaw where the system accepts memory operations that should be restricted based on the segment's protection flags. This bypass occurs during the memory mapping and caching process where the kernel fails to cross-check the actual memory protection settings against the requested access patterns, allowing malicious applications to perform unauthorized read-write operations on memory segments that should remain read-only.
The operational impact of this vulnerability is significant as it enables attackers to bypass intended access restrictions and potentially escalate privileges within the system. An attacker with a crafted application could exploit this weakness to gain unauthorized access to memory segments that should be protected, potentially leading to information disclosure, system compromise, or privilege escalation. The vulnerability is particularly concerning because it operates at the kernel level where memory protection mechanisms are fundamental to system security. This flaw could be leveraged to access sensitive system data, manipulate kernel memory, or create persistent backdoors within the operating system's memory space.
From a cybersecurity perspective, this vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a classic case of insufficient privilege checking in kernel-level memory management. The attack vector typically involves a malicious application that carefully crafts memory operations to exploit the cache mode handling logic, potentially using techniques such as memory corruption or manipulation of shared memory segments. The vulnerability also maps to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" through kernel-level exploits that bypass system protection mechanisms.
Mitigation strategies should focus on applying the official security updates from Apple that address the kernel memory management flaw. System administrators should ensure immediate deployment of iOS 8.1.3, OS X 10.10.2, and Apple TV 7.0.3 updates which contain the necessary patches to enforce proper memory protection attributes. Additionally, organizations should implement monitoring for suspicious memory access patterns and consider runtime protection mechanisms that can detect anomalous shared memory operations. The vulnerability underscores the importance of proper kernel memory management and reinforces the need for rigorous testing of memory protection mechanisms, particularly in systems that handle sensitive data and operate in security-critical environments.