CVE-2016-1861 in Mac OS X
Summary
by MITRE
The NVIDIA Graphics Drivers subsystem in Apple OS X before 10.11.5 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app, a different vulnerability than CVE-2016-1846.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability identified as CVE-2016-1861 represents a critical security flaw within the NVIDIA Graphics Drivers subsystem integrated into Apple macOS operating systems prior to version 10.11.5. This issue specifically affects the kernel-level graphics driver components that facilitate hardware acceleration and graphics processing within the macOS environment. The vulnerability stems from inadequate input validation and memory management practices within the graphics driver implementation, creating a pathway for malicious code execution with elevated privileges. Security researchers have classified this as a privilege escalation vulnerability due to its ability to execute code in a privileged context, which typically operates with system-level access and administrative capabilities. The flaw manifests when a specially crafted application attempts to interact with the graphics driver through improper memory handling or buffer manipulation techniques.
The technical exploitation of CVE-2016-1861 occurs through a carefully constructed malicious application that leverages memory corruption vulnerabilities within the NVIDIA graphics driver kernel extension. This vulnerability falls under the CWE-119 category of "Improper Access to Memory" and specifically relates to improper handling of memory buffers during graphics processing operations. Attackers can craft applications that trigger memory corruption conditions when the graphics driver processes specific graphics commands or data structures, leading to unpredictable behavior in the kernel space. The memory corruption typically manifests as stack or heap corruption, potentially allowing attackers to overwrite critical kernel memory locations or manipulate execution flow. This type of vulnerability is particularly dangerous because it operates at the kernel level where the executing code possesses the highest privilege levels, potentially enabling complete system compromise. The vulnerability is distinct from CVE-2016-1846, indicating separate code paths and exploitation techniques within the same graphics driver subsystem.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system stability and security implications for macOS users. When exploited, the vulnerability can result in arbitrary code execution with root privileges, enabling attackers to install malicious software, modify system files, or establish persistent backdoors within the target system. The memory corruption aspect also presents a risk of denial of service conditions where system stability is compromised through kernel crashes or memory exhaustion attacks. Organizations and individual users running affected macOS versions face significant security risks as attackers can leverage this vulnerability to gain unauthorized access to sensitive system resources. The vulnerability's presence in graphics drivers is particularly concerning because graphics processing is a fundamental system function that applications frequently utilize, increasing the attack surface and potential exploitation vectors.
Mitigation strategies for CVE-2016-1861 primarily focus on updating to the patched version of macOS, specifically Apple OS X 10.11.5 or later, which includes fixes for the graphics driver memory handling issues. System administrators should prioritize deployment of the security patches released by Apple to address the vulnerability. Additional protective measures include implementing application whitelisting policies to restrict execution of untrusted graphics-intensive applications and monitoring for suspicious graphics driver behavior through system logs and security monitoring tools. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs. Organizations should also consider disabling unnecessary graphics acceleration features and implementing regular security assessments to identify potential exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date system components and highlights the risks associated with kernel-level vulnerabilities in graphics drivers, which are often overlooked in traditional security assessments. This vulnerability aligns with ATT&CK techniques related to privilege escalation and persistence mechanisms, emphasizing the need for comprehensive security controls that address both user-space and kernel-level threats.