CVE-2021-30909 in macOS
Summary
by MITRE • 08/25/2021
A memory corruption issue was addressed with improved memory handling. This issue is fixed in iOS 15.1 and iPadOS 15.1, macOS Monterey 12.0.1, iOS 14.8.1 and iPadOS 14.8.1, tvOS 15.1, watchOS 8.1, Security Update 2021-007 Catalina, macOS Big Sur 11.6.1. An application may be able to execute arbitrary code with kernel privileges.
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Analysis
by VulDB Data Team • 10/31/2021
This vulnerability represents a critical memory corruption flaw that existed within Apple's operating system kernels across multiple platforms including iOS, iPadOS, macOS, tvOS, and watchOS. The issue stems from inadequate memory handling mechanisms that could potentially allow malicious applications to exploit memory management weaknesses and escalate privileges to kernel level access. The vulnerability was specifically addressed through enhanced memory management protocols and improved kernel security controls in the respective software updates. According to industry standards, this type of vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write vulnerabilities, both of which are common vectors for privilege escalation attacks. The ATT&CK framework categorizes this under privilege escalation techniques where adversaries leverage memory corruption vulnerabilities to gain elevated system privileges.
The technical implementation of this vulnerability demonstrates how improper memory handling can create exploitable conditions within kernel space operations. When applications interact with kernel memory regions, inadequate bounds checking or memory allocation validation can result in corrupted memory states that malicious code can manipulate to execute arbitrary instructions with the highest system privileges. This type of flaw typically occurs when kernel functions fail to properly validate memory access requests or when memory deallocation processes do not adequately secure memory regions. The exploitation requires an application to first gain execution privileges on the system, then leverage the memory corruption to transition from user space to kernel space where system-level operations can be performed. The fix implemented by Apple involved strengthening memory allocation routines, implementing additional bounds checking mechanisms, and enhancing kernel memory protection protocols.
The operational impact of this vulnerability extends beyond simple privilege escalation as it represents a potential pathway for sophisticated attacks that could compromise entire operating systems. Once an attacker achieves kernel-level execution, they can bypass all standard security controls, modify system files, install persistent backdoors, and access all user data without detection. The vulnerability affects multiple Apple platforms simultaneously, indicating a systemic issue within the kernel memory management architecture that required coordinated patching across all supported operating systems. Organizations and individuals using affected versions of Apple software were at risk of sophisticated attacks that could lead to complete system compromise and data theft. The security update release pattern shows Apple's approach to addressing critical kernel vulnerabilities through immediate patch deployment across all affected platforms.
Mitigation strategies for this vulnerability require immediate implementation of the security updates provided by Apple, as the memory corruption issue cannot be effectively addressed through configuration changes or network security controls alone. System administrators should prioritize patch deployment across all affected devices including iOS devices, macOS systems, and other Apple platforms. The vulnerability's nature as a kernel-level memory corruption means that traditional endpoint protection solutions may not provide adequate defense against exploitation attempts. Organizations should implement comprehensive monitoring for suspicious system behavior and ensure that all Apple devices are maintained with the latest security patches. The fix addresses the root cause through improved memory handling rather than workarounds, making it essential for all users to apply the updates immediately to prevent exploitation. Security teams should also consider implementing device management policies that enforce automatic update deployment to minimize exposure windows.