CVE-2020-9974 in macOS
Summary
by MITRE • 12/09/2020
A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.0.1, iOS 14.2 and iPadOS 14.2, tvOS 14.2, watchOS 7.1. A malicious application may be able to determine kernel memory layout.
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Analysis
by VulDB Data Team • 12/17/2020
This vulnerability represents a logic flaw in the kernel memory management subsystem of Apple's operating systems, specifically affecting versions prior to the security releases mentioned in the advisory. The issue stems from inadequate state management mechanisms that fail to properly enforce memory access controls and kernel address space protections. Such flaws typically arise when the operating system's kernel fails to maintain consistent internal states during memory operations, creating potential pathways for unauthorized memory inspection. The vulnerability allows a malicious application to potentially determine kernel memory layout information through improper state handling during memory management operations, which constitutes a significant information disclosure risk.
The technical implementation of this vulnerability involves the kernel's memory management subsystem failing to properly track or validate memory state transitions, particularly when handling kernel memory mappings and virtual address space operations. When an application attempts to interact with kernel memory structures, the improper state management allows for information leakage about kernel memory layout through side-channel observations or memory inspection techniques. This issue falls under the CWE-254 category of security weaknesses related to inadequate state management and memory protection mechanisms. The vulnerability represents a logic error rather than a traditional buffer overflow or injection flaw, making it more subtle and potentially harder to detect through standard security scanning methods.
The operational impact of this vulnerability extends beyond simple information disclosure, as knowledge of kernel memory layout can significantly aid attackers in developing more sophisticated exploits. An attacker who successfully leverages this vulnerability could potentially use the leaked memory layout information to bypass kernel address space layout randomization kASLR protections, making subsequent kernel exploitation attempts much more likely to succeed. This type of information disclosure vulnerability aligns with ATT&CK technique T1059.003 for kernel memory manipulation and T1068 for local privilege escalation. The vulnerability could enable attackers to craft more effective kernel exploits, potentially leading to full system compromise, especially when combined with other vulnerabilities or when targeting specific kernel memory structures.
Mitigation strategies for this vulnerability require immediate deployment of the security updates provided by Apple, specifically macOS Big Sur 11.0.1, iOS 14.2, iPadOS 14.2, tvOS 14.2, and watchOS 7.1. System administrators should prioritize patching all affected devices in their environment, as this vulnerability represents a potential pathway to system compromise. Additionally, organizations should implement monitoring for suspicious application behavior that might attempt to exploit memory layout information disclosure. While the vulnerability requires a malicious application to be present on the system, the potential for privilege escalation makes it critical to maintain up-to-date system patches. Network security controls should also be configured to prevent unauthorized application installation on affected systems until patches are deployed, as this vulnerability specifically relates to malicious applications being able to exploit the kernel memory management logic.