CVE-2018-4236 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.5 is affected. The issue involves the "IOGraphics" 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 • 03/20/2023
The vulnerability identified as CVE-2018-4236 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.13.5. This issue resides within the IOGraphics component which serves as a fundamental graphics subsystem responsible for managing display drivers and graphics hardware interfaces. The vulnerability stems from improper input validation and memory handling within this privileged system component that governs how graphics-related data is processed and managed. Attackers can exploit this weakness by crafting malicious applications that leverage the flawed graphics processing pathways to gain unauthorized access to privileged execution contexts. The security implications extend beyond simple code execution as the vulnerability also presents potential for denial of service conditions through memory corruption attacks that could destabilize the entire graphics subsystem.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in heap-based memory structures. The flaw manifests when the IOGraphics component processes specially crafted graphics data or driver requests that exceed allocated memory boundaries, leading to unpredictable memory corruption. This type of vulnerability falls under the ATT&CK technique T1059.003 for Command and Scripting Interpreter, specifically targeting the execution of arbitrary code in privileged contexts. The vulnerability's exploitation pathway leverages the graphics subsystem's elevated privileges, allowing attackers to bypass standard security boundaries that typically protect system-level processes from user-space applications. The memory corruption aspect can result in system crashes, application instability, or more severe consequences when the corrupted memory structures are subsequently accessed by legitimate system processes.
The operational impact of CVE-2018-4236 extends significantly beyond individual system compromise, as it affects the foundational graphics processing capabilities of macOS environments. Organizations relying on affected macOS versions face potential for widespread system instability, particularly in enterprise environments where graphics-intensive applications are common. The vulnerability's ability to cause memory corruption means that successful exploitation could lead to persistent system issues that might require complete system reinstallation to resolve. Additionally, the privileged execution context allows attackers to potentially escalate their access to other system resources, making this vulnerability particularly dangerous for targeted attacks against high-value assets. The affected IOGraphics component's role in managing display drivers and hardware interfaces also means that exploitation could potentially compromise hardware-level security features, creating long-term security implications for affected systems.
Mitigation strategies for CVE-2018-4236 primarily focus on immediate system updates to macOS 10.13.5 or later versions where Apple has implemented proper input validation and memory management fixes for the IOGraphics component. System administrators should prioritize deployment of the official security patches released by Apple, as these updates address the underlying buffer overflow conditions that enable the exploit. Additional defensive measures include implementing application whitelisting policies that restrict execution of unsigned or untrusted applications that might leverage graphics processing capabilities. Network-level monitoring should be enhanced to detect unusual graphics-related system calls or memory allocation patterns that could indicate exploitation attempts. The vulnerability also underscores the importance of maintaining current system patch management procedures, as this flaw demonstrates how graphics subsystem vulnerabilities can provide attackers with privileged execution capabilities. Organizations should also consider implementing sandboxing measures for graphics-intensive applications and regularly audit system configurations to ensure that outdated graphics drivers are not present on affected systems.