CVE-2016-4678 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.1 is affected. The issue involves the "AppleSMC" component. It allows local users to gain privileges or cause a denial of service (NULL pointer dereference) via unspecified vectors.
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Analysis
by VulDB Data Team • 09/28/2022
The vulnerability identified as CVE-2016-4678 resides within Apple's macOS operating system, specifically affecting versions prior to 10.12.1. This issue is categorized under the AppleSMC (Apple System Management Controller) component, which serves as a critical subsystem responsible for managing low-level hardware functions including temperature monitoring, fan control, and power management. The AppleSMC component operates with elevated privileges and maintains direct hardware access, making it a prime target for privilege escalation attacks. The vulnerability manifests as a NULL pointer dereference condition that occurs when the system processes certain inputs or commands through the SMC interface. This flaw represents a fundamental software error where the system attempts to access memory at a null address, leading to system instability and potential privilege escalation opportunities. The vulnerability's impact extends beyond simple denial of service as it provides local attackers with pathways to elevate their privileges within the operating system. According to CWE classification, this vulnerability maps to CWE-476 which describes NULL pointer dereference conditions, while the ATT&CK framework would categorize this under privilege escalation techniques using system component exploitation. The SMC component's role in hardware management means that any successful exploitation could potentially allow attackers to manipulate critical system functions such as thermal monitoring, power states, and hardware configuration parameters.
The technical exploitation of CVE-2016-4678 occurs when local users can trigger specific sequences that cause the AppleSMC driver to attempt operations on uninitialized or invalid memory pointers. This particular NULL pointer dereference vulnerability allows attackers to either crash the system through denial of service or potentially escalate privileges by leveraging the elevated permissions associated with the SMC component. The attack vector is particularly concerning because it requires only local system access, meaning that any user with login credentials can potentially exploit this vulnerability. The flaw demonstrates poor input validation and memory management practices within the AppleSMC subsystem, where the code fails to properly validate pointer references before dereferencing them. This type of vulnerability is particularly dangerous in system management components because these drivers often run with kernel-level privileges and have unrestricted access to hardware resources. The implications of such a vulnerability extend to both availability and integrity aspects of the system, as attackers could disrupt normal operations while simultaneously gaining unauthorized access to system functions that should remain protected.
The operational impact of CVE-2016-4678 represents a significant security risk for macOS environments, particularly in enterprise settings where multiple users may have local access to systems. Organizations running affected versions of macOS face potential risks including system instability, unexpected reboots, and unauthorized privilege escalation that could allow attackers to execute malicious code with system-level privileges. The vulnerability's local nature means that it can be exploited without requiring network access or sophisticated attack infrastructure, making it particularly attractive to malicious actors. From a security posture perspective, this vulnerability undermines the principle of least privilege as it allows local users to potentially gain elevated system access. The impact is compounded by the fact that the AppleSMC component is integral to system operation, meaning that exploitation could affect core system functionality including power management, thermal control, and hardware monitoring capabilities. Security professionals should note that this vulnerability represents a classic example of how low-level system components can create significant security risks when proper memory management and input validation practices are not implemented. The vulnerability also highlights the importance of regular system updates and patch management, as the issue was resolved in macOS 10.12.1 and subsequent releases.
Mitigation strategies for CVE-2016-4678 primarily focus on immediate remediation through system updates to macOS 10.12.1 or later versions where the vulnerability has been patched. System administrators should prioritize deployment of the official Apple security updates that address this specific NULL pointer dereference in the AppleSMC component. Additionally, organizations should implement comprehensive patch management processes that ensure all macOS systems remain current with security updates. Network segmentation and user access controls can provide additional defense-in-depth measures to limit local access privileges where possible. Monitoring systems should be configured to detect unusual system behavior or unexpected reboots that could indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date system software and implementing robust security practices for operating system management. Organizations should also consider implementing automated patch deployment solutions to minimize the window of exposure for such vulnerabilities. Regular security assessments of system components, particularly those with elevated privileges and direct hardware access, can help identify potential weaknesses before they can be exploited by malicious actors. The remediation process should include verification that the patches have been successfully applied and that systems are no longer vulnerable to this specific class of NULL pointer dereference attacks.