CVE-2019-8829 in tvOS
Summary
by MITRE • 10/28/2020
A memory corruption vulnerability was addressed with improved locking. This issue is fixed in macOS Catalina 10.15.1, Security Update 2019-001, and Security Update 2019-006, watchOS 6.1, tvOS 13.2, iOS 13.2 and iPadOS 13.2. 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 locking mechanisms within the operating system's kernel components, creating potential race conditions and memory management inconsistencies that adversaries could exploit. The vulnerability affects multiple Apple operating systems including macOS Catalina, watchOS, tvOS, and iOS, indicating a widespread impact across the Apple ecosystem. The memory corruption occurs during kernel operations where proper synchronization mechanisms were insufficient to prevent concurrent access patterns that could lead to unpredictable memory states.
The technical nature of this vulnerability aligns with common weakness enumerations such as CWE-119, which addresses memory corruption issues, and CWE-362, which covers race conditions that can lead to privilege escalation. Attackers could potentially leverage this flaw through carefully crafted applications that trigger specific memory access patterns, causing the kernel to execute malicious code with the highest privilege level. The exploitation requires an application to be running on the affected system, making it a local privilege escalation vulnerability that could be particularly dangerous in environments where users have the ability to install applications. The fix implemented by Apple involved strengthening the locking mechanisms to prevent concurrent access to sensitive kernel memory regions, thereby eliminating the race conditions that enabled the memory corruption.
The operational impact of CVE-2019-8829 extends beyond simple privilege escalation as it represents a fundamental breakdown in the kernel's memory management security model. Systems running vulnerable versions of Apple's operating systems face potential compromise through applications that could be installed by users or delivered through malicious software. This vulnerability particularly affects enterprise environments where users might have elevated privileges or where the operating system is used in security-sensitive contexts. The fact that multiple operating systems share this vulnerability indicates that Apple's kernel memory management was affected across different device types, from desktop computers to mobile devices and embedded systems.
The mitigation strategy for this vulnerability requires immediate deployment of the security updates provided by Apple, including macOS Catalina 10.15.1, Security Update 2019-001, Security Update 2019-006, watchOS 6.1, tvOS 13.2, iOS 13.2, and iPadOS 13.2. Organizations should prioritize patching across all affected systems and implement monitoring for potential exploitation attempts. The fix addresses the underlying synchronization issues in the kernel's memory management subsystem, ensuring that concurrent access to critical memory regions is properly controlled. Security teams should also consider implementing application whitelisting policies to prevent installation of untrusted applications that could potentially exploit this vulnerability, as the attack vector requires an application to be running on the system. The vulnerability demonstrates the critical importance of proper kernel locking mechanisms and the potential consequences when such protections are insufficient, aligning with ATT&CK technique T1068 which covers privilege escalation through kernel exploits.