CVE-2019-8759 in macOS
Summary
by MITRE • 10/28/2020
An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006, macOS Catalina 10.15. A local user may be able to cause unexpected system termination or read kernel memory.
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Analysis
by VulDB Data Team • 01/31/2024
The vulnerability identified as CVE-2019-8759 represents a critical out-of-bounds read flaw within the macOS kernel implementation that could potentially compromise system stability and security. This issue manifests when the operating system processes certain data structures without proper validation of array bounds, creating opportunities for malicious actors to exploit the weakness. The vulnerability specifically affects macOS versions prior to the security updates released in late 2019, making it a significant concern for organizations running older system versions. The flaw falls under the category of memory safety issues that are commonly addressed through bounds checking mechanisms, which are fundamental to preventing unauthorized memory access patterns.
The technical nature of this vulnerability stems from insufficient input validation within kernel-level processes that handle system data structures. When legitimate system operations attempt to access memory regions beyond their allocated boundaries, the system may experience unexpected behavior including crashes or the exposure of sensitive kernel memory contents. This type of flaw typically arises from programming errors where developers fail to properly validate array indices or buffer limits before accessing memory locations. The issue is particularly dangerous because it operates at the kernel level where unauthorized memory access could reveal confidential system information or allow for privilege escalation attacks. According to CWE classification, this vulnerability maps to CWE-129 which specifically addresses insufficient bounds checking in input validation scenarios.
The operational impact of CVE-2019-8759 extends beyond simple system instability to potentially enable more sophisticated attack vectors. A local user with minimal privileges could exploit this vulnerability to cause system crashes that might be leveraged for denial-of-service attacks or to gather kernel memory information that could aid in further exploitation attempts. The vulnerability's potential for causing unexpected system termination creates opportunities for attackers to disrupt normal operations while simultaneously providing access to sensitive kernel data that could be used to understand system internals and develop more targeted attacks. This makes the flaw particularly concerning for enterprise environments where system reliability and security are paramount.
Organizations should prioritize immediate deployment of the available security updates that address this vulnerability, specifically macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006. These patches implement enhanced bounds checking mechanisms that prevent the out-of-bounds memory access conditions that previously enabled exploitation. System administrators should also consider implementing additional monitoring to detect potential exploitation attempts and ensure that all endpoints are properly updated. The mitigation strategy should include regular security patch management processes and continuous monitoring for similar vulnerabilities that might be present in other system components. From an ATT&CK framework perspective, this vulnerability could be leveraged in initial access or privilege escalation phases of an attack, making proactive patching essential for maintaining security posture.