CVE-2016-4706 in macOS
Summary
by MITRE
cd9660 in Apple OS X before 10.12 allows local users to cause a denial of service via unspecified vectors.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-4706 affects the cd9660 filesystem driver within Apple's macOS operating system versions prior to 10.12. This flaw resides in the handling of ISO 9660 filesystem structures which are commonly used for optical disc images and other storage media. The cd9660 filesystem implementation is responsible for managing read-only filesystem operations and maintaining compatibility with various optical disc formats including cdrom and dvdrom. The vulnerability represents a denial of service condition that can be triggered by local users through unspecified vectors, indicating a potential weakness in input validation or resource management within the filesystem driver.
The technical nature of this vulnerability stems from insufficient bounds checking or improper handling of malformed filesystem structures within the cd9660 implementation. When a local user presents specially crafted filesystem data or attempts to access specific filesystem structures, the kernel-level driver fails to properly validate the input parameters or may encounter an unhandled exception during processing. This type of vulnerability falls under the category of improper input validation and can be classified as a CWE-129 weakness related to insufficient validation of array indices. The lack of proper error handling in the filesystem driver creates an opportunity for a local attacker to manipulate the system's filesystem processing capabilities and potentially cause system instability or complete system hang conditions.
The operational impact of this vulnerability extends beyond simple denial of service as it affects the core filesystem functionality of the operating system. Local users who can exploit this vulnerability may cause the system to become unresponsive or require manual rebooting to recover from the denial of service condition. This vulnerability is particularly concerning because it operates at the kernel level within the filesystem driver, meaning that successful exploitation could potentially lead to more severe consequences including system crashes or privilege escalation scenarios. The attack surface is broad as any local user with access to the system can potentially trigger this condition, making it a significant concern for system administrators and security professionals.
Mitigation strategies for CVE-2016-4706 primarily focus on updating to Apple macOS version 10.12 or later where the vulnerability has been addressed through proper bounds checking and input validation mechanisms. System administrators should implement comprehensive patch management procedures to ensure all systems receive the necessary security updates promptly. Additionally, monitoring for unusual filesystem access patterns or system performance degradation may help detect potential exploitation attempts. The vulnerability demonstrates the importance of maintaining current operating system versions and implementing proper access controls to limit local user privileges where possible. This issue aligns with ATT&CK technique T1068 which involves local privilege escalation and system compromise through kernel-level vulnerabilities, emphasizing the critical nature of addressing such foundational security flaws in operating system components.