CVE-2019-8523 in iCloud
Summary
by MITRE
Multiple memory corruption issues were addressed with improved memory handling. This issue is fixed in iOS 12.2, tvOS 12.2, Safari 12.1, iTunes 12.9.4 for Windows, iCloud for Windows 7.11. Processing maliciously crafted web content may lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 05/21/2020
The vulnerability identified as CVE-2019-8523 represents a critical memory corruption issue that affected multiple Apple operating systems and applications. This vulnerability resides in the core memory management mechanisms of iOS 12.1, tvOS 12.1, Safari 12.0, and iTunes 12.9.3 for Windows, creating a significant attack surface that could be exploited by malicious actors. The flaw specifically manifests when these systems process maliciously crafted web content, potentially allowing attackers to execute arbitrary code on targeted devices. The issue falls under the category of memory safety vulnerabilities, which are particularly dangerous as they can lead to complete system compromise and unauthorized access to sensitive user data.
The technical implementation of this vulnerability stems from inadequate memory handling procedures within Apple's web rendering and processing components. When Safari or other affected applications encounter specially crafted web content, the flawed memory management code fails to properly validate or sanitize input data structures, leading to memory corruption conditions. This type of vulnerability is classified as a memory corruption flaw under CWE-122, which specifically addresses improper handling of memory allocation and deallocation operations. The memory corruption occurs during the parsing and rendering of web content, where buffer overflows or use-after-free conditions may be triggered by malformed HTML, JavaScript, or multimedia elements embedded within the malicious payload.
The operational impact of CVE-2019-8523 extends beyond simple application crashes or data corruption, as it enables full arbitrary code execution capabilities for attackers. This means that an attacker who successfully exploits this vulnerability could gain complete control over the affected device, potentially installing malware, accessing personal data, monitoring user activities, or using the compromised system as a launch point for further attacks. The attack vector is particularly concerning because it leverages web-based delivery mechanisms, making it possible to exploit the vulnerability through email attachments, malicious websites, or compromised web applications. According to ATT&CK framework, this vulnerability maps to technique T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter), as it allows attackers to execute commands through compromised web browsers.
The remediation for this vulnerability required Apple to implement improved memory handling procedures across all affected platforms, including enhanced input validation, stricter memory allocation controls, and more robust sanitization of web content processing. The fix was deployed through iOS 12.2, tvOS 12.2, Safari 12.1, iTunes 12.9.4 for Windows, and iCloud for Windows 7.11 updates, which introduced additional safeguards against memory corruption conditions. Organizations should prioritize immediate deployment of these security updates, as the vulnerability represents a significant risk to user privacy and system integrity. Security professionals should also implement network monitoring to detect potential exploitation attempts and maintain awareness of related vulnerabilities that may leverage similar memory handling flaws. The remediation approach aligns with industry best practices for memory safety and follows the principle of least privilege in memory management, which is essential for preventing exploitation of such fundamental system vulnerabilities.