CVE-2016-7633 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.2 is affected. The issue involves the "Directory Services" component. It allows local users to gain privileges or cause a denial of service (use-after-free) via unspecified vectors.
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Analysis
by VulDB Data Team • 09/19/2024
The vulnerability identified as CVE-2016-7633 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.12.2. This issue resides within the Directory Services component which serves as a fundamental system service responsible for managing network directories and user authentication within Apple's ecosystem. The vulnerability manifests as a use-after-free condition that occurs when the system improperly handles memory management during specific operations within the Directory Services framework. Such memory corruption vulnerabilities are particularly dangerous because they can be exploited to execute arbitrary code or cause system instability.
The technical nature of this vulnerability places it squarely within the CWE-416 category of use-after-free conditions, which occurs when a program continues to reference memory after it has been freed, leading to unpredictable behavior and potential exploitation. The flaw exists in how the Directory Services component manages memory allocation and deallocation processes, particularly when handling certain directory queries or authentication requests. Attackers can leverage this vulnerability through local user access, meaning no network connectivity or remote exploitation is required. The attack vector typically involves crafting specific inputs or operations that trigger the memory corruption when the Directory Services daemon processes these requests.
From an operational impact perspective, this vulnerability creates significant risks for macOS systems as it provides local attackers with potential privilege escalation capabilities or denial of service conditions. The use-after-free condition could enable an attacker with local login access to escalate their privileges to system level, potentially gaining root access to the affected system. Alternatively, the vulnerability could be exploited to cause a system crash or reboot, leading to denial of service for legitimate users. This makes the vulnerability particularly concerning in enterprise environments where local access might be more readily available or where system availability is critical. The vulnerability affects the core system services that manage user authentication and directory access, making it a fundamental threat to system integrity.
Security professionals should implement immediate mitigations including updating to macOS 10.12.2 or later versions where Apple has patched the vulnerability through proper memory management corrections. The patch addresses the underlying use-after-free condition by ensuring proper memory deallocation and validation before memory access. Organizations should also consider implementing additional security controls such as monitoring for unusual directory service activity or implementing privilege separation mechanisms. The vulnerability demonstrates the importance of proper memory management in system services and highlights the need for comprehensive code review processes. From an ATT&CK framework perspective, this vulnerability relates to privilege escalation techniques and denial of service tactics, making it relevant to both the privilege escalation and execution phases of an attack lifecycle. System administrators should prioritize this patch deployment as a high-priority security measure, particularly in environments where local access controls may be less restrictive.