CVE-2020-9844 in macOS
Summary
by MITRE
A double free issue was addressed with improved memory management. This issue is fixed in iOS 13.5 and iPadOS 13.5, macOS Catalina 10.15.5. A remote attacker may be able to cause unexpected system termination or corrupt kernel memory.
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Analysis
by VulDB Data Team • 10/20/2020
The vulnerability identified as CVE-2020-9844 represents a critical double free memory corruption issue that affects Apple's mobile and desktop operating systems. This flaw manifests in the kernel memory management subsystem where improper handling of memory allocation and deallocation operations creates conditions for malicious exploitation. The vulnerability specifically impacts iOS 13.5 and iPadOS 13.5, as well as macOS Catalina 10.15.5, indicating a widespread issue across Apple's ecosystem that requires immediate attention from system administrators and security professionals.
The technical nature of this double free vulnerability stems from the improper memory management practices within the kernel components that handle memory allocation requests. When the system processes memory deallocation operations, it fails to properly track memory blocks, leading to scenarios where the same memory region can be freed twice. This condition creates unpredictable behavior in the kernel memory allocator, potentially allowing an attacker to manipulate memory layout and execute arbitrary code with kernel privileges. The flaw falls under CWE-415 which specifically addresses double free conditions in memory management, making it a well-documented and dangerous class of vulnerability that has been exploited in numerous high-profile attacks.
The operational impact of CVE-2020-9844 extends beyond simple system instability, presenting a significant threat to system integrity and user data security. A remote attacker capable of exploiting this vulnerability can cause unexpected system termination, which may result in denial of service conditions, or more critically, corrupt kernel memory in ways that could enable privilege escalation attacks. This memory corruption could potentially allow an attacker to execute malicious code with the highest system privileges, effectively compromising the entire operating system and all user data stored on the device. The remote exploitation capability means that attackers do not require physical access to the target device, making this vulnerability particularly dangerous in mobile environments where devices are frequently exposed to untrusted networks and applications.
Mitigation strategies for CVE-2020-9844 primarily focus on applying the official security updates released by Apple, which include iOS 13.5, iPadOS 13.5, and macOS Catalina 10.15.5. These updates implement improved memory management procedures that prevent the double free conditions from occurring by strengthening memory tracking mechanisms and implementing additional validation checks within the kernel's memory allocator. Organizations should prioritize immediate deployment of these patches across all affected systems, particularly in enterprise environments where mobile devices and macOS systems are extensively used. Additionally, security monitoring should be enhanced to detect unusual system behavior that might indicate exploitation attempts, and network segmentation should be maintained to limit potential attack vectors. The vulnerability also aligns with ATT&CK technique T1068 which covers local privilege escalation, making it a critical target for defensive security teams implementing comprehensive threat hunting programs.