CVE-2019-8591 in watchOS
Summary
by MITRE
A type confusion issue was addressed with improved memory handling. This issue is fixed in iOS 12.3, macOS Mojave 10.14.5, tvOS 12.3, watchOS 5.2.1. An application may be able to cause unexpected system termination or write kernel memory.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2019-8591 represents a critical type confusion flaw that existed within Apple's operating systems, specifically affecting iOS 12.2 and earlier versions, macOS Mojave 10.14.4 and earlier, tvOS 12.2 and earlier, and watchOS 5.2 and earlier. This issue stems from inadequate memory handling mechanisms that fail to properly distinguish between different data types during runtime operations, creating opportunities for malicious code to exploit the system's memory management subsystem. The vulnerability manifests when an application attempts to manipulate memory objects without proper type validation, leading to unpredictable behavior that can result in system instability or unauthorized kernel memory access.
The technical nature of this vulnerability aligns with CWE-466, which describes the improper handling of type confusion scenarios where a program incorrectly treats data of one type as if it were another type. This type confusion occurs at the memory management level where the system fails to maintain proper type safety when processing objects in memory. The flaw allows an attacker to craft malicious applications that can manipulate memory addresses and object types in ways that were not anticipated by the system's design, potentially enabling arbitrary code execution or privilege escalation. The vulnerability is particularly concerning because it can be triggered by ordinary applications, meaning that any app installed on an affected system could potentially exploit this weakness to cause system-wide instability.
The operational impact of CVE-2019-8591 extends beyond simple system crashes or unexpected terminations, as the vulnerability can enable attackers to write to kernel memory spaces. This capability represents a significant security risk because kernel memory access allows for direct manipulation of the operating system's core functions and can potentially lead to full system compromise. The vulnerability creates opportunities for attackers to escalate privileges, bypass security protections, or execute malicious code with system-level privileges. From an attacker's perspective, this flaw represents a valuable exploit primitive that can be combined with other vulnerabilities to achieve more sophisticated attacks, making it particularly dangerous in threat actor toolkits.
The mitigation for this vulnerability involved updating affected Apple operating systems to versions that included improved memory handling mechanisms and enhanced type validation. Apple addressed the issue by implementing stricter memory management protocols that prevent type confusion scenarios from occurring in the first place. The fixes included modifications to how the system handles memory objects, particularly in the kernel memory management subsystem, and enhanced validation checks that ensure data types are properly maintained throughout the application lifecycle. These updates align with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and demonstrates how memory corruption vulnerabilities can be exploited to gain elevated system privileges. Organizations should ensure all affected systems are updated to the patched versions including iOS 12.3, macOS Mojave 10.14.5, tvOS 12.3, and watchOS 5.2.1 to prevent exploitation of this vulnerability.