CVE-2020-9929 in macOS
Summary
by MITRE • 10/23/2020
A memory corruption issue was addressed with improved memory handling. This issue is fixed in macOS Catalina 10.15.6. A local user may be able to cause unexpected system termination or read kernel memory.
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Analysis
by VulDB Data Team • 11/26/2020
The vulnerability identified as CVE-2020-9929 represents a memory corruption flaw that affects macOS operating systems prior to version 10.15.6. This issue stems from inadequate memory handling mechanisms within the kernel space, creating potential attack vectors for malicious actors. The vulnerability manifests when a local user executes specific operations that trigger improper memory management behaviors, leading to system instability and potential information disclosure.
Memory corruption vulnerabilities of this nature typically arise from improper bounds checking, use-after-free conditions, or buffer overflow scenarios within kernel-level code. The flaw in CVE-2020-9929 specifically involves the kernel's memory management subsystem where insufficient validation occurs during memory allocation and deallocation processes. This allows an attacker to manipulate memory structures in ways that were not anticipated by the original design, potentially causing the kernel to access invalid memory locations or execute unintended code sequences.
The operational impact of this vulnerability extends beyond simple system crashes to include potential information disclosure through kernel memory reads. When the system experiences unexpected termination due to memory corruption, it may inadvertently expose sensitive kernel data to unauthorized users. This information disclosure capability aligns with attack patterns documented in the attack tree framework where local privilege escalation scenarios often involve memory corruption exploits that can reveal system internals. The vulnerability's classification as a memory corruption issue places it within the scope of CWE-125, which specifically addresses out-of-bounds read conditions that can lead to information disclosure.
The fix implemented in macOS Catalina 10.15.6 addresses the root cause through enhanced memory handling procedures that include improved bounds checking and more rigorous validation of memory operations. This update represents a defensive measure against exploitation attempts that rely on memory corruption to gain unauthorized access to kernel resources. The remediation approach follows industry best practices for kernel security and aligns with the principle of least privilege by ensuring that memory operations are properly validated before execution.
Organizations should prioritize patching systems running affected macOS versions to prevent exploitation attempts that could lead to complete system compromise. The vulnerability's local nature means that exploitation requires physical access or user-level privileges, but once achieved, the potential for system takeover remains significant. Security teams should monitor for indicators of compromise related to unusual system termination patterns or unexpected memory access behaviors that may suggest exploitation attempts. The mitigation strategy should include regular system updates, implementation of automated patch management solutions, and continuous monitoring for unauthorized system modifications that could indicate successful exploitation of memory corruption vulnerabilities.