CVE-2014-4403 in Mac OS X
Summary
by MITRE
The kernel in Apple OS X before 10.9.5 allows local users to obtain sensitive address information and bypass the ASLR protection mechanism by leveraging predictability of the location of the CPU Global Descriptor Table.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/22/2024
The vulnerability described in CVE-2014-4403 represents a significant security flaw in Apple's operating system kernel that undermines fundamental memory protection mechanisms. This issue affects Apple OS X versions prior to 10.9.5 and specifically targets the kernel's handling of memory addressing structures, creating a pathway for local attackers to bypass critical security controls.
The technical flaw stems from the predictability of the CPU Global Descriptor Table (GDT) location within kernel memory space. The GDT is a critical data structure used by x86 processors to define memory segments and their access permissions. In vulnerable versions of macOS, the kernel's implementation allows attackers to determine the memory addresses of kernel components through careful analysis of the GDT's predictable placement. This predictability directly compromises Address Space Layout Randomization (ASLR), a crucial defense mechanism designed to randomize the memory layout of processes and make exploitation of memory corruption vulnerabilities significantly more difficult.
The operational impact of this vulnerability is severe as it enables local attackers to bypass ASLR protection, which is a cornerstone of modern exploit mitigation strategies. When ASLR is defeated, attackers can more easily craft successful exploits against kernel vulnerabilities, as they no longer need to perform complex address discovery techniques to locate kernel functions and data structures. This vulnerability operates at the kernel level, meaning successful exploitation could lead to privilege escalation and full system compromise. The flaw specifically affects the kernel's memory management subsystem, making it particularly dangerous for attackers who might otherwise struggle with the complexity of kernel exploitation.
The vulnerability aligns with CWE-122, which addresses improper restriction of operations within a memory buffer, and relates to the broader category of memory corruption vulnerabilities that target kernel memory management. From an ATT&CK perspective, this vulnerability maps to T1068, which covers 'Exploitation for Privilege Escalation', and T1059, covering 'Command and Scripting Interpreter', as attackers could leverage this to gain elevated privileges and execute malicious code. The predictability of kernel memory locations also connects to T1106, 'Execution through API', as attackers could potentially use this information to manipulate kernel function calls and data structures.
The mitigation approach for this vulnerability primarily involves updating to Apple OS X 10.9.5 or later versions where the kernel memory management has been patched to eliminate the predictability of GDT locations. Additionally, system administrators should implement comprehensive monitoring for unusual memory access patterns and kernel activity that might indicate exploitation attempts. The patch addresses the root cause by modifying the kernel's memory layout randomization algorithms to ensure that the Global Descriptor Table location cannot be predicted by local attackers, thereby restoring effective ASLR protection mechanisms. Organizations should also consider implementing additional security controls such as kernel extension signing requirements and enhanced monitoring of kernel-level activities to further protect against similar vulnerabilities.