CVE-2019-8847 in macOS
Summary
by MITRE • 10/28/2020
A memory corruption issue was addressed with improved memory handling. This issue is fixed in macOS Catalina 10.15.2, Security Update 2019-002 Mojave, and Security Update 2019-007 High Sierra. An application may be able to execute arbitrary code with kernel privileges.
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Analysis
by VulDB Data Team • 11/29/2020
This memory corruption vulnerability represents a critical security flaw that could enable malicious applications to escalate privileges and execute arbitrary code with kernel-level access. The issue stems from inadequate memory handling mechanisms within the macOS operating system kernel, creating potential attack vectors for privilege escalation exploits. The vulnerability affects multiple versions of macOS including Catalina 10.15.2, Mojave with Security Update 2019-002, and High Sierra with Security Update 2019-007, indicating a widespread impact across the operating system's kernel memory management subsystem. The flaw allows applications to manipulate kernel memory structures in ways that should not be permitted under normal security boundaries, effectively breaking the isolation between user-space processes and kernel-space operations.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow in heap-based memory. These classifications indicate that the memory corruption occurs within heap memory management areas where applications can potentially overwrite kernel memory structures. The root cause involves improper validation of memory operations and insufficient bounds checking during kernel memory allocation and deallocation processes. Attackers could exploit this by crafting malicious applications that trigger specific memory access patterns, leading to memory corruption that allows arbitrary code execution with elevated privileges. This type of vulnerability is particularly dangerous because it operates at the kernel level where all system security mechanisms are bypassed.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise. When an application achieves kernel-level execution, it gains unrestricted access to all system resources, including the ability to read and modify any file, access network connections, manipulate system processes, and potentially install persistent backdoors. The vulnerability creates a persistent threat vector that could be exploited by malware authors, nation-state actors, or other malicious entities seeking to establish long-term system control. Organizations running affected macOS versions face significant risk of data breaches, system hijacking, and complete loss of system integrity. The exploitation of such vulnerabilities often requires minimal user interaction, making them particularly dangerous in environments where users may unknowingly execute malicious code.
Mitigation strategies should focus on immediate patching of all affected systems with the respective security updates provided by Apple. System administrators must prioritize deployment of macOS Catalina 10.15.2, Security Update 2019-002 for Mojave, and Security Update 2019-007 for High Sierra. Additional defensive measures include implementing application whitelisting policies, monitoring for unusual kernel-level activities, and maintaining regular security audits of system configurations. Organizations should also consider network segmentation and privilege separation to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the importance of continuous security monitoring and rapid patch deployment as outlined in the ATT&CK framework's privilege escalation techniques, particularly those involving kernel exploits and memory corruption attacks that leverage operating system vulnerabilities to gain system-level control.