CVE-2019-8740 in tvOS
Summary
by MITRE • 10/28/2020
A memory corruption vulnerability was addressed with improved locking. This issue is fixed in iOS 13.1 and iPadOS 13.1, watchOS 6, tvOS 13. An application may be able to execute arbitrary code with kernel privileges.
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Analysis
by VulDB Data Team • 11/28/2020
The vulnerability identified as CVE-2019-8740 represents a critical memory corruption flaw that existed within Apple's operating systems prior to version 13.1. This issue stems from inadequate locking mechanisms within the kernel-level components of iOS, iPadOS, watchOS, and tvOS. The flaw allows a malicious application to potentially escalate privileges and execute arbitrary code with kernel-level access, fundamentally compromising the security model of these platforms. The vulnerability was particularly concerning because it could be exploited by any application installed on the device, making it a widespread threat across all affected Apple operating systems.
The technical implementation of this vulnerability involves improper synchronization mechanisms that govern access to shared kernel memory resources. When multiple threads or processes attempt to access the same memory location simultaneously without proper locking protocols, the system can enter an inconsistent state where memory corruption occurs. This type of flaw falls under the CWE-362 category of Concurrent Execution using Shared Resource with Unprotected Shared Data, which specifically addresses race conditions in multi-threaded environments. The lack of adequate locking mechanisms creates a window of opportunity where malicious code can manipulate memory contents before proper synchronization occurs, leading to unpredictable behavior and potential privilege escalation.
The operational impact of CVE-2019-8740 extends far beyond typical application-level vulnerabilities due to its kernel-level nature and the privilege escalation it enables. Once exploited, an application could gain complete control over the device's core operating system functions, including access to all user data, network communications, and system resources. This represents a severe compromise of the security architecture that Apple employs to protect user privacy and device integrity. The vulnerability could enable attackers to install persistent backdoors, steal sensitive information, monitor user activities, and potentially compromise other connected devices in the network. The fact that this vulnerability affects multiple Apple platforms including mobile devices, wearables, and television systems amplifies its potential impact across various attack vectors and user scenarios.
Apple addressed this vulnerability through comprehensive improvements to their kernel locking mechanisms and memory management protocols in iOS 13.1, iPadOS 13.1, watchOS 6, and tvOS 13. The fix involved implementing more robust synchronization primitives that prevent concurrent access to sensitive kernel memory regions without proper mutual exclusion. This remediation aligns with the ATT&CK framework's mitigation strategies for privilege escalation techniques, particularly those involving kernel exploits and memory corruption attacks. Security professionals should ensure all affected devices are updated immediately to prevent exploitation, as the vulnerability could be leveraged by sophisticated threat actors without requiring user interaction or specific conditions. Organizations should also implement monitoring solutions to detect potential exploitation attempts and maintain comprehensive incident response procedures for handling potential compromises of their Apple device fleets.