CVE-2016-4709 in macOS
Summary
by MITRE
WindowServer in Apple OS X before 10.12 allows local users to obtain root access via vectors that leverage "type confusion," a different vulnerability than CVE-2016-4710.
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Analysis
by VulDB Data Team • 09/21/2022
The vulnerability identified as CVE-2016-4709 represents a critical type confusion flaw within Apple's WindowServer component of macOS operating systems prior to version 10.12. This issue resides in the core graphics rendering subsystem that manages window operations and user interface elements across the desktop environment. The WindowServer process operates with elevated privileges to handle graphical operations, making it a prime target for privilege escalation attacks. Type confusion vulnerabilities occur when a program incorrectly handles data types during memory operations, leading to unpredictable behavior that attackers can exploit to execute arbitrary code with higher privileges.
The technical exploitation of this vulnerability leverages the fundamental flaw in how WindowServer processes certain data structures during graphical operations. Attackers can manipulate input parameters to cause the system to interpret memory locations incorrectly, potentially allowing them to overwrite critical system structures or execute malicious code within the privileged WindowServer context. This type confusion manifests when the system's memory management routines fail to properly validate data types, creating opportunities for attackers to manipulate program flow and gain unauthorized access to system resources. The vulnerability differs from CVE-2016-4710 in its specific implementation approach, yet both represent the same underlying class of memory safety issues affecting the graphics subsystem.
The operational impact of CVE-2016-4709 is severe as it provides local attackers with a pathway to achieve root privileges without requiring additional authentication or complex attack vectors. Once exploited, successful exploitation grants full system control including the ability to modify system files, install malware, access sensitive data, and potentially compromise the entire computing environment. This vulnerability particularly affects enterprise environments where macOS systems are deployed, as local access often requires minimal effort to achieve. The WindowServer process typically runs continuously with system-level privileges, making it an attractive target for attackers seeking persistent access to systems.
Mitigation strategies for CVE-2016-4709 primarily focus on applying the official security patches released by Apple for macOS 10.12 and later versions. System administrators should prioritize updating affected systems and implementing proper access controls to limit local user privileges where possible. The vulnerability aligns with CWE-468, which categorizes type confusion as a memory safety issue, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves local privilege escalation through system vulnerabilities. Organizations should also consider implementing network monitoring to detect anomalous graphical process behavior and maintain regular security assessments of their macOS environments to identify similar memory corruption vulnerabilities. The patch addresses the underlying memory management issues in WindowServer's handling of data structures, preventing the type confusion that enables privilege escalation attacks.