CVE-2016-4649 in Mac OS X
Summary
by MITRE
Audio in Apple OS X before 10.11.6 allows local users to cause a denial of service (NULL pointer dereference) via unspecified vectors.
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Analysis
by VulDB Data Team • 09/06/2022
The vulnerability identified as CVE-2016-4649 represents a critical denial of service flaw affecting Apple macOS versions prior to 10.11.6. This issue resides within the audio subsystem of the operating system, specifically manifesting as a NULL pointer dereference condition that can be exploited by local attackers to disrupt system operations. The vulnerability's impact extends beyond simple service disruption as it can potentially lead to system instability and complete denial of service for audio-related functionalities. The unspecified vectors suggest that multiple attack paths may exist within the audio processing pipeline, making the vulnerability particularly concerning for security professionals tasked with protecting macOS environments.
From a technical perspective, the NULL pointer dereference occurs when the audio subsystem attempts to access memory locations that have not been properly initialized or allocated. This type of vulnerability falls under the common weakness enumeration CWE-476 which specifically addresses NULL pointer dereference conditions. The flaw represents a fundamental programming error where the system fails to validate pointer values before attempting to dereference them, creating an opportunity for malicious actors to manipulate the audio processing components. The local nature of this vulnerability means that attackers must already have access to the system, typically through legitimate user accounts or administrative privileges, but the impact can be severe enough to compromise system availability.
The operational implications of CVE-2016-4649 extend beyond immediate denial of service conditions to encompass broader system stability concerns. When the audio subsystem crashes due to NULL pointer dereference, it can potentially affect other system components that depend on audio services or trigger cascading failures within the operating system. This vulnerability aligns with ATT&CK technique T1499 which covers denial of service attacks and can be particularly problematic in enterprise environments where audio functionality is critical for various applications and services. The vulnerability's presence in macOS versions prior to 10.11.6 indicates that it was present in multiple iterations of the operating system, suggesting that the audio subsystem contained fundamental flaws in its memory management and pointer validation processes.
Security mitigation strategies for this vulnerability primarily focus on system updates and patch management. Apple's release of macOS 10.11.6 addressed the underlying issue through proper pointer validation and memory management improvements within the audio subsystem. Organizations should prioritize immediate deployment of this update to protect their systems from exploitation. Additionally, system administrators can implement monitoring solutions to detect unusual audio subsystem behavior that might indicate attempted exploitation of this vulnerability. The vulnerability serves as a reminder of the importance of maintaining current operating system versions and implementing comprehensive patch management policies to prevent exploitation of known weaknesses in system components. Network security teams should also consider this vulnerability when conducting risk assessments for macOS environments, particularly in scenarios where local access might be compromised or where privileged accounts exist within the system.