CVE-2017-7021 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.6 is affected. The issue involves the "AppleGraphicsPowerManagement" component. It allows attackers to execute arbitrary code in a privileged context or cause a denial of service (memory corruption) via a crafted app.
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Analysis
by VulDB Data Team • 01/05/2021
The vulnerability identified as CVE-2017-7021 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.12.6. This issue specifically targets the AppleGraphicsPowerManagement component which serves as a crucial subsystem responsible for managing graphics hardware power states and related functionalities within the operating system. The vulnerability exists within the kernel-level graphics power management framework, making it particularly dangerous as it operates at the core of system security mechanisms.
The technical flaw manifests through a memory corruption vulnerability that occurs when the AppleGraphicsPowerManagement component processes specially crafted input from malicious applications. This memory corruption vulnerability stems from inadequate bounds checking and input validation within the graphics power management code paths. Attackers can exploit this weakness by developing a malicious application that triggers specific sequences of graphics power management operations, leading to buffer overflows or other memory corruption conditions. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which allows attackers to manipulate memory layout and potentially execute arbitrary code with kernel-level privileges.
The operational impact of this vulnerability is severe and multifaceted, as it enables attackers to achieve privilege escalation from standard user context to kernel-level execution. This privilege escalation capability means that an attacker could execute malicious code with the highest system privileges, potentially leading to complete system compromise. The vulnerability also presents a denial of service vector, where the memory corruption could cause system crashes or instability, disrupting normal operations. This dual nature of the vulnerability makes it particularly attractive to threat actors as it provides both persistent access and system disruption capabilities. The attack surface is widened by the fact that the vulnerability can be triggered through seemingly benign applications, making detection and prevention challenging.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1055 for privilege escalation and T1499 for denial of service. The exploitation pattern follows common attack methodologies where initial access is gained through legitimate application execution, followed by privilege escalation to kernel level. Security professionals should note that this vulnerability was part of a broader class of graphics driver vulnerabilities that have historically been difficult to patch due to the complex nature of graphics hardware integration. The remediation approach requires immediate system updates to macOS 10.12.6 or later versions, as Apple released specific security patches addressing the memory corruption issues within the AppleGraphicsPowerManagement component. Organizations should prioritize patch management for macOS systems, particularly those running versions prior to 10.12.6, as the vulnerability represents a significant risk to system integrity and data security. Additionally, network monitoring should be enhanced to detect suspicious application behavior that might indicate exploitation attempts, and system administrators should implement proper access controls and application whitelisting policies to minimize the attack surface.