CVE-2019-8718 in tvOS
Summary
by MITRE • 10/28/2020
A memory corruption issue was addressed with improved memory handling. This issue is fixed in watchOS 6, iOS 13, 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
This vulnerability represents a critical memory corruption flaw that existed in Apple's mobile operating systems, specifically affecting iOS 12 and earlier versions, watchOS 5 and earlier, and tvOS 12 and earlier. The issue stems from inadequate memory handling mechanisms that could be exploited by malicious applications to gain unauthorized access to kernel-level privileges. The vulnerability falls under the category of memory safety issues that are commonly classified as CWE-122, which deals with buffer overflow conditions, or more specifically CWE-787, which addresses out-of-bounds write operations. The flaw represents a significant escalation path from user-space to kernel-space execution, allowing an application to bypass normal security boundaries and execute arbitrary code with the highest system privileges.
The technical exploitation of this vulnerability occurs when an application can manipulate memory allocation and deallocation processes in a way that leads to memory corruption. This typically involves crafting malicious input or manipulating data structures to cause buffer overflows, use-after-free conditions, or other memory management errors that can be leveraged to overwrite critical kernel memory regions. Attackers could potentially use this vulnerability to execute code with kernel privileges, effectively gaining complete control over the device and bypassing all standard security protections. The exploitation requires sophisticated knowledge of the target system's memory layout and can be achieved through carefully crafted application code that triggers the memory corruption condition.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it represents a fundamental breach in the operating system's security model. Once an attacker successfully exploits this vulnerability, they gain unrestricted access to all device data, can install malicious applications, monitor user activities, and potentially exfiltrate sensitive information. The vulnerability affects all devices running the affected operating system versions, making it particularly dangerous given the widespread deployment of these systems. From an attacker's perspective, this represents a highly valuable exploit that can be used for persistent surveillance, data theft, or as a stepping stone for further attacks on connected networks or other devices.
The fix for this vulnerability was implemented through improved memory handling mechanisms in the respective operating system updates. Apple's patch addresses the underlying memory corruption issues by implementing stricter bounds checking, improved memory allocation algorithms, and enhanced validation of memory operations. The mitigation strategy involves upgrading to the patched versions of iOS 13, watchOS 6, and tvOS 13, which contain the necessary security improvements to prevent exploitation of this memory corruption flaw. Organizations should prioritize immediate deployment of these updates to protect their device fleets, as the vulnerability represents a significant risk to device security and data integrity. The remediation aligns with ATT&CK technique T1059, which covers command and scripting interpreter, as the exploitation could enable attackers to execute arbitrary commands with elevated privileges, and T1068, which addresses exploit for privilege escalation.