CVE-2017-2421 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.4 is affected. The issue involves the "AppleGraphicsPowerManagement" component. A race condition allows attackers to execute arbitrary code in a privileged context via a crafted app.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2017-2421 represents a critical race condition flaw within Apple's macOS operating system affecting versions prior to 10.12.4. This security issue resides within the AppleGraphicsPowerManagement component which governs graphics power management functionality on Apple devices. The race condition occurs during the processing of graphics power management operations where insufficient synchronization mechanisms allow for improper execution flow. Attackers can exploit this weakness by crafting a malicious application that triggers the race condition during graphics power management operations, thereby gaining the ability to execute arbitrary code with elevated privileges. The vulnerability specifically targets the kernel-level graphics power management subsystem, making it particularly dangerous as it operates within the most privileged execution context of the operating system.
The technical exploitation of this vulnerability leverages a fundamental flaw in the timing and synchronization of power management operations within the graphics driver subsystem. When the AppleGraphicsPowerManagement component processes graphics power state changes, the race condition manifests during the transition between different power states where multiple threads or processes may access shared resources simultaneously without proper locking mechanisms. This creates an opportunity for malicious code to manipulate memory locations or function pointers that are being modified during the race window, potentially allowing attackers to redirect execution flow or inject malicious code into the privileged execution context. The flaw is classified as a race condition under CWE-362, which specifically addresses concurrent execution issues that can lead to privilege escalation and arbitrary code execution. The vulnerability operates at the kernel level where the graphics power management code executes with root privileges, making successful exploitation particularly devastating.
The operational impact of CVE-2017-2421 extends beyond simple privilege escalation as it provides attackers with a powerful foothold for further compromise within macOS environments. Once successfully exploited, the malicious code can manipulate graphics drivers, modify system memory, or establish persistent backdoors that persist across reboots. The vulnerability affects all Apple devices running macOS versions before 10.12.4 including MacBook Air, MacBook Pro, Mac mini, and Mac Pro models. This represents a significant concern for enterprise environments where macOS devices are commonly used as workstations and servers, as the privilege escalation capability allows attackers to bypass standard user access controls and potentially access sensitive data or system resources. The attack vector requires only a crafted application that can be delivered through various means including malicious downloads, social engineering campaigns, or compromised software installations.
Mitigation strategies for CVE-2017-2421 focus primarily on immediate system updates and operational security measures. The most effective remediation involves updating affected macOS systems to version 10.12.4 or later where Apple has implemented proper synchronization mechanisms to address the race condition. Organizations should prioritize patch management to ensure all macOS devices are updated promptly, as the vulnerability remains exploitable in older versions. Additional security controls include implementing application whitelisting policies that restrict execution of unsigned or untrusted applications, monitoring for suspicious graphics power management activity, and maintaining network segmentation to limit the lateral movement capabilities of attackers who might gain initial access through this vulnerability. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be used to establish persistence within the system. Security teams should monitor for indicators of compromise related to unusual graphics power management processes or unexpected privilege escalation events, as these activities may signal exploitation attempts. The vulnerability highlights the importance of thorough code review and testing of kernel-level components, particularly those handling system-level resource management operations.