CVE-2019-8647 in iOS
Summary
by MITRE
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 12.4, tvOS 12.4, watchOS 5.3. A remote attacker may be able to cause arbitrary code execution.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2019-8647 represents a critical use-after-free condition that existed in Apple's mobile operating systems. This type of memory safety issue occurs when a program continues to reference memory that has already been freed or deallocated, creating potential opportunities for malicious exploitation. The flaw was particularly concerning because it could be exploited remotely, meaning attackers did not need physical access to target devices to carry out attacks. The vulnerability affected iOS 12.3 and earlier versions, tvOS 12.3 and earlier versions, and watchOS 5.2 and earlier versions, indicating it was present across Apple's mobile ecosystem. The issue stems from inadequate memory management practices where the system failed to properly track memory references after deallocation, creating a window of opportunity for attackers to manipulate program execution flow. According to CWE classification, this vulnerability maps to CWE-416 which specifically addresses the use of freed memory condition. The remote code execution capability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow attackers to execute arbitrary code on compromised devices. The fix implemented by Apple involved strengthening memory management controls and ensuring proper reference counting mechanisms were in place to prevent the reuse of freed memory blocks. This type of vulnerability is particularly dangerous in mobile environments where devices handle sensitive personal data and often maintain persistent connections to network services. The remote exploitation capability means that attackers could potentially compromise devices through malicious websites, email attachments, or network-based attacks without requiring user interaction beyond normal browsing activities. The remediation approach taken by Apple focused on improving the underlying memory management subsystem to prevent the specific conditions that led to the use-after-free scenario. Security researchers have noted that such vulnerabilities often require sophisticated exploitation techniques, as modern operating systems implement various protections like stack canaries, address space layout randomization, and heap metadata protections. The vulnerability highlights the importance of proper memory management in preventing critical security flaws and demonstrates how seemingly simple memory handling errors can lead to significant remote execution capabilities. Organizations should ensure all affected systems are updated to the patched versions immediately, as the window of opportunity for exploitation existed for all versions prior to iOS 12.4, tvOS 12.4, and watchOS 5.3. The incident underscores the need for continuous security monitoring and prompt patch deployment to maintain system integrity against evolving threats.