CVE-2019-8662 in iOS
Summary
by MITRE
This issue was addressed with improved checks. This issue is fixed in iOS 12.4, macOS Mojave 10.14.6, tvOS 12.4, watchOS 5.3. An attacker may be able to trigger a use-after-free in an application deserializing an untrusted NSDictionary.
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Analysis
by VulDB Data Team • 01/23/2025
The vulnerability identified as CVE-2019-8662 represents a critical use-after-free condition that emerged in Apple's operating systems, specifically affecting iOS versions prior to 12.4, macOS Mojave 10.14.6, tvOS 12.4, and watchOS 5.3. This flaw resides in the handling of untrusted NSDictionary objects during the deserialization process, creating a pathway for malicious actors to exploit memory management inconsistencies within Apple's software ecosystem. The vulnerability demonstrates the classic characteristics of a use-after-free attack vector where an application continues to reference memory that has already been freed, potentially allowing for arbitrary code execution or system compromise.
The technical root cause of this vulnerability lies in insufficient input validation and memory management during the deserialization of NSDictionary objects. When applications process untrusted dictionary data structures, the improper handling of memory allocation and deallocation creates opportunities for attackers to manipulate the memory state and trigger the use-after-free condition. This type of vulnerability falls under the CWE-416 category, which specifically addresses the use of freed memory condition, and aligns with the ATT&CK framework's technique T1059.007 for command and scripting interpreter, as exploitation could enable attackers to execute malicious code within the application's memory space. The flaw particularly affects applications that deserialize user-provided or network-retrieved dictionary data without adequate sanitization or validation measures.
The operational impact of CVE-2019-8662 extends beyond simple application-level compromise to potentially affect entire system security postures. Attackers could leverage this vulnerability to execute arbitrary code with the privileges of the compromised application, potentially escalating to system-level access depending on the target application's permissions and capabilities. The vulnerability's exploitation requires the attacker to craft malicious NSDictionary objects that, when processed by vulnerable applications, trigger the memory management error. This could occur through various attack vectors including malicious email attachments, compromised web content, or manipulated file downloads that are subsequently processed by applications utilizing the affected deserialization routines.
Apple's remediation for this vulnerability involved implementing enhanced input validation and memory management checks during the NSDictionary deserialization process. The fix ensures that proper memory allocation and deallocation procedures are maintained throughout the object lifecycle, preventing the conditions that lead to use-after-free scenarios. Organizations should prioritize updating all affected systems to the patched versions, as the vulnerability could be exploited in the wild without user interaction, making proactive patch management essential. Security teams should monitor for any potential exploitation attempts and consider implementing additional network-based protections or application whitelisting measures to mitigate risk until full deployment of the patches is achieved. The remediation approach aligns with industry best practices for memory safety and demonstrates the importance of robust input validation in preventing exploitation of memory corruption vulnerabilities.