CVE-2019-8824 in macOS
Summary
by MITRE • 10/28/2020
A memory corruption issue was addressed with improved state management. This issue is fixed in macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006. An application may be able to execute arbitrary code with kernel privileges.
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Analysis
by VulDB Data Team • 11/29/2020
The vulnerability identified as CVE-2019-8824 represents a critical memory corruption flaw that existed within the macOS operating system kernel. This issue stems from inadequate state management mechanisms that allowed malicious applications to exploit memory handling inconsistencies. The vulnerability was particularly concerning because it could be leveraged by an attacker to escalate privileges from user-level applications to kernel-level execution, effectively granting complete system control. The memory corruption occurred due to improper handling of kernel memory structures during specific operational states, creating exploitable conditions that bypassed normal security boundaries.
The technical nature of this vulnerability aligns with CWE-122, which describes improper restriction of operations within a memory buffer, and CWE-119, which covers weaknesses in memory management that enable buffer overflows. The flaw manifested when applications attempted to interact with kernel memory regions under certain conditions, leading to unpredictable memory states that could be manipulated by malicious code. Attackers could potentially trigger this condition through crafted application code that exercised specific memory allocation and deallocation patterns, causing the kernel to execute arbitrary code with elevated privileges. This type of vulnerability is classified under the ATT&CK technique T1068, which covers 'Local Port/Service Discovery' and 'Exploitation for Privilege Escalation', as it specifically enables privilege escalation through kernel exploitation.
The operational impact of CVE-2019-8824 was significant given that it affected macOS versions prior to Catalina 10.15.1 and the corresponding security updates. Systems running vulnerable versions were at risk of complete compromise, as successful exploitation would allow attackers to bypass all kernel-level security controls including code signing enforcement, sandboxing mechanisms, and other privilege separation features. The vulnerability's exploitation required minimal user interaction since it could be triggered through normal application execution, making it particularly dangerous in environments where users might run untrusted software. Organizations with macOS systems needed immediate remediation through the installation of Security Update 2019-001 or Security Update 2019-006 to address the memory management flaws and prevent potential exploitation.
Mitigation strategies for this vulnerability centered on immediate patch deployment as the primary defense mechanism, with additional security measures including network segmentation, application whitelisting, and monitoring for suspicious kernel activity. System administrators should have implemented comprehensive patch management procedures to ensure all macOS systems received the necessary security updates. The fix involved enhanced state management protocols within the kernel memory subsystem that properly validated memory operations and prevented the corruption conditions that previously enabled privilege escalation. Organizations also benefited from implementing additional monitoring solutions to detect potential exploitation attempts and maintain audit logs of kernel-level activities that could indicate compromise. Security teams should have reviewed their incident response procedures to prepare for potential exploitation attempts and established protocols for rapid system recovery in case of successful attacks.