CVE-2015-7078 in Mac OS X
Summary
by MITRE
Use-after-free vulnerability in Hypervisor in Apple OS X before 10.11.2 allows local users to gain privileges via vectors involving VM objects.
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Analysis
by VulDB Data Team • 06/22/2024
The CVE-2015-7078 vulnerability represents a critical use-after-free flaw within Apple's hypervisor implementation in macOS versions prior to 10.11.2. This vulnerability exists in the virtual machine management subsystem where the operating system handles virtual machine objects and their lifecycle management. The flaw allows local attackers to exploit improper memory management practices that occur when virtual machine objects are deallocated but still referenced by other components within the hypervisor layer. The vulnerability specifically manifests when the hypervisor attempts to access memory regions that have already been freed, creating a scenario where arbitrary code execution becomes possible through carefully crafted exploitation techniques. This represents a fundamental breakdown in memory safety mechanisms within the kernel-level hypervisor component that governs virtual machine operations.
The technical implementation of this vulnerability stems from inadequate reference counting and object lifecycle management within the hypervisor's virtual machine object handling code. When virtual machine objects are destroyed or deallocated, the system fails to properly invalidate all references to these objects before memory is released back to the system. Attackers can leverage this by creating specific sequences of virtual machine operations that cause the hypervisor to access freed memory locations, potentially leading to privilege escalation from local user context to kernel-level privileges. This type of vulnerability falls under the CWE-416 category of Use After Free, which is classified as a serious memory safety issue that can result in arbitrary code execution. The attack vector involves local users who can manipulate virtual machine objects through legitimate system interfaces, making the exploitation relatively accessible compared to remote attacks.
The operational impact of CVE-2015-7078 is significant as it enables local privilege escalation attacks that can compromise the entire system. An attacker with local access can leverage this vulnerability to execute code with kernel privileges, potentially gaining complete control over the affected macOS system. This includes the ability to bypass system security controls, install malicious software, access sensitive data, and modify system configurations without detection. The vulnerability affects all macOS versions before 10.11.2, making it particularly dangerous as it impacts a substantial portion of the installed base. The hypervisor-based nature of the flaw means that any application or process running on the system that interacts with virtual machine functionality can potentially be exploited, including legitimate virtualization tools and sandboxed applications that utilize the hypervisor layer.
Mitigation strategies for CVE-2015-7078 primarily focus on system updates and operational security measures. The most effective immediate solution is upgrading to macOS 10.11.2 or later versions where Apple has implemented proper memory management fixes for the hypervisor component. Organizations should also implement strict patch management policies to ensure all systems receive timely security updates. Additionally, system administrators should monitor for unauthorized virtual machine operations and restrict access to virtualization features where possible. The vulnerability highlights the importance of kernel memory safety practices and proper object lifecycle management in operating system components. From a defensive perspective, implementing runtime monitoring for suspicious memory access patterns and using exploit prevention techniques can help detect and prevent exploitation attempts. This vulnerability underscores the critical need for comprehensive security testing of kernel-level components, particularly those handling virtualization and memory management functions, as outlined in the ATT&CK framework's kernel-mode rootkit and privilege escalation techniques.