CVE-2020-9908 in macOS
Summary
by MITRE • 10/23/2020
An out-of-bounds read was addressed with improved input validation. 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-2020-9908 represents a critical out-of-bounds read flaw within the macOS operating system kernel. This type of vulnerability falls under the broader category of memory safety issues and is particularly dangerous because it occurs at the kernel level where arbitrary code execution or system instability can result from improper memory access patterns. The flaw affects macOS Catalina versions prior to 10.15.6, indicating that attackers could potentially exploit this weakness to gain unauthorized access to kernel memory spaces or cause system crashes through malformed inputs.
The technical nature of this vulnerability stems from insufficient input validation mechanisms within kernel components responsible for processing user-space requests. When legitimate system calls or data processing operations encounter malformed or unexpectedly large input data, the kernel fails to properly bounds-check memory accesses before reading from allocated memory regions. This allows a local attacker with user-level privileges to craft specific inputs that trigger memory read operations beyond allocated boundaries, potentially exposing sensitive kernel memory contents or causing system crashes. The issue is classified under CWE-129 as an insufficient input validation vulnerability, specifically manifesting as an out-of-bounds read condition.
The operational impact of CVE-2020-9908 extends beyond simple system instability to potentially enable more sophisticated attacks. While the immediate effect may appear as unexpected system termination, the underlying memory exposure could allow attackers to extract kernel memory contents, which might contain sensitive information such as encryption keys, credential storage locations, or other system-critical data. This vulnerability particularly concerns security professionals because it represents a local privilege escalation vector that could be leveraged to bypass security controls and gain elevated system privileges. The attack surface is significant as it affects all macOS Catalina installations before the patched version, making it a widespread concern for enterprise environments and individual users alike.
Organizations and users should prioritize immediate remediation by updating to macOS Catalina 10.15.6 or later versions where this vulnerability has been addressed through improved input validation mechanisms. The fix implemented by Apple likely includes enhanced bounds checking routines and stricter validation of kernel input parameters to prevent memory access violations. Security teams should also implement monitoring for unusual system termination patterns or memory access anomalies that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and defense evasion, as attackers could potentially use such flaws to establish persistence or hide malicious activities within kernel memory spaces. Additional mitigations include implementing system integrity protection measures, monitoring for unauthorized kernel module loading, and maintaining up-to-date security patches across all macOS installations to prevent exploitation of similar memory safety vulnerabilities in the future.