CVE-2019-8661 in macOS
Summary
by MITRE
A use after free issue was addressed with improved memory management. This issue is fixed in macOS Mojave 10.14.6. A remote attacker may be able to cause arbitrary code execution.
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Analysis
by VulDB Data Team • 01/05/2025
The vulnerability identified as CVE-2019-8661 represents a critical use-after-free flaw in Apple's macOS operating system that was officially disclosed in 2019. This type of vulnerability occurs when a program continues to reference memory that has already been freed or deallocated, creating a dangerous condition that can be exploited by malicious actors. The issue specifically affected macOS Mojave versions prior to 10.14.6, where the operating system's memory management mechanisms failed to properly handle certain memory deallocation sequences. The vulnerability falls under the CWE-416 category of use-after-free conditions, which is classified as a common weakness in software security practices. According to the ATT&CK framework, this vulnerability could be leveraged as part of a remote code execution technique, specifically categorized under T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation.
The technical implementation of this use-after-free vulnerability stems from improper memory management within macOS components that handle memory allocation and deallocation processes. When certain applications or system processes interact with memory regions that are subsequently freed, the system fails to properly invalidate references to that memory, allowing an attacker to manipulate the freed memory space. This creates a scenario where an attacker can overwrite or corrupt memory contents with malicious data, potentially leading to arbitrary code execution. The remote exploitation capability means that an attacker does not need physical access to the target system, as the vulnerability can be triggered through network-based attacks. The flaw likely existed in kernel-level memory management functions or in specific system services that handle user input or network communications, making it particularly dangerous as it could be exploited by attackers without requiring local system access.
The operational impact of CVE-2019-8661 extends beyond simple system instability, as successful exploitation could result in complete system compromise and unauthorized access to sensitive data. An attacker who successfully exploits this vulnerability could execute arbitrary code with the privileges of the compromised process, potentially escalating privileges to system-level access. This vulnerability particularly affects enterprise environments where macOS systems are prevalent, as it could be leveraged to establish persistent access to corporate networks. The remote execution capability makes it especially concerning for organizations that do not maintain strict network segmentation policies, as attackers could potentially compromise systems from external networks. Security researchers have noted that use-after-free vulnerabilities of this nature often serve as stepping stones for more sophisticated attacks, as they can be used to deploy additional malware or establish backdoors within the compromised environment.
Apple's response to this vulnerability involved implementing improved memory management practices in macOS Mojave version 10.14.6, which addressed the root cause of the use-after-free condition. Organizations should prioritize immediate deployment of the macOS 10.14.6 update to mitigate this risk, as the vulnerability remains exploitable in older versions. System administrators should also implement network monitoring to detect potential exploitation attempts, as use-after-free vulnerabilities often produce characteristic patterns in system logs or network traffic. Additional mitigations include maintaining strict software update policies, implementing network segmentation to limit potential attack surfaces, and conducting regular security assessments of macOS environments. The vulnerability highlights the importance of regular security updates and proper memory management practices in operating system development, as similar issues have been identified in other software platforms and have led to numerous security incidents throughout the industry.