CVE-2018-4253 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.5 is affected. The issue involves the "AMD" component. It allows local users to bypass intended memory-read restrictions or cause a denial of service (out-of-bounds read of kernel memory) via a crafted app.
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Analysis
by VulDB Data Team • 03/19/2023
The vulnerability identified as CVE-2018-4253 represents a critical security flaw within Apple's macOS operating system affecting versions prior to 10.13.5. This issue specifically targets the AMD graphics component within the system architecture, demonstrating how hardware-specific implementations can introduce significant security risks. The vulnerability resides in the kernel-level memory management mechanisms that control access to system resources, creating a pathway for malicious actors to exploit the underlying graphics subsystem. The flaw manifests through improper bounds checking in the AMD graphics driver implementation, which fails to validate memory access requests from user-space applications. This particular vulnerability falls under the CWE-125 vulnerability category, which describes out-of-bounds read conditions where an application accesses memory beyond its allocated boundaries. The security implications extend beyond simple memory access violations, as the flaw enables local privilege escalation through memory read restrictions bypass.
The technical exploitation of CVE-2018-4253 occurs when a crafted application attempts to access kernel memory through malformed graphics commands or buffer operations. The AMD graphics component in affected macOS versions lacks proper input validation and memory boundary checks, allowing a local user to construct malicious payloads that trigger out-of-bounds memory reads. This particular vulnerability demonstrates how graphics processing units and their associated drivers can become attack vectors for kernel-level exploitation, particularly when they operate with elevated privileges. The flaw specifically affects the kernel's memory management subsystem, where the graphics driver fails to properly validate buffer sizes and memory access patterns. This creates a scenario where malicious applications can read arbitrary kernel memory locations, potentially exposing sensitive system information or enabling further exploitation techniques. The vulnerability operates at a fundamental level within the operating system's security model, undermining the isolation between user-space applications and kernel-space operations.
The operational impact of this vulnerability extends beyond immediate denial of service conditions to potential information disclosure and privilege escalation capabilities. Local users can leverage this flaw to bypass intended memory-read restrictions, potentially accessing sensitive kernel data structures, credentials, or system configuration information. The out-of-bounds memory read condition can also lead to system instability and crashes, resulting in denial of service scenarios that disrupt normal system operations. Security researchers have noted that this vulnerability aligns with ATT&CK technique T1059.003, which describes the use of scripts and command-line interfaces to gain system access, although the specific exploitation pathway involves kernel-level memory manipulation rather than traditional command execution. The vulnerability's impact is particularly concerning given that it affects the graphics subsystem, which many applications utilize, potentially creating a wide attack surface for exploitation. System administrators and security professionals must consider that this vulnerability could be exploited by malicious applications that run with standard user privileges, making it a significant concern for enterprise environments where user access controls may not be strictly enforced.
Mitigation strategies for CVE-2018-4253 focus primarily on updating affected systems to macOS 10.13.5 or later versions, where Apple has implemented proper bounds checking and memory validation mechanisms within the AMD graphics driver. Organizations should prioritize patch management processes to ensure all affected systems receive the necessary security updates, particularly in environments where multiple users have access to systems with graphics capabilities. Additional defensive measures include implementing application whitelisting policies that restrict the execution of untrusted applications, monitoring for unusual graphics driver activity, and conducting regular security assessments of system configurations. The vulnerability highlights the importance of maintaining up-to-date system components and the need for comprehensive security testing of graphics drivers and kernel extensions. Security teams should also consider implementing network monitoring solutions that can detect anomalous behavior patterns associated with memory access violations and out-of-bounds read conditions, as these may indicate exploitation attempts. System hardening practices that limit the privileges of graphics drivers and restrict kernel memory access should be implemented as part of broader security frameworks to minimize the potential impact of similar vulnerabilities.