CVE-2021-30674 in iOS
Summary
by MITRE • 09/08/2021
This issue was addressed with improved checks. This issue is fixed in iOS 14.6 and iPadOS 14.6. A malicious application may disclose restricted memory.
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Analysis
by VulDB Data Team • 09/08/2021
This vulnerability represents a critical memory disclosure flaw that could potentially allow attackers to access sensitive system resources through a malicious application. The issue stems from inadequate memory access controls within the iOS operating system, specifically affecting versions prior to 14.6. When a malicious application attempts to access restricted memory regions, the system fails to properly enforce access boundaries, creating an avenue for unauthorized data exposure. This type of vulnerability falls under the broader category of information disclosure weaknesses that can compromise system integrity and confidentiality. The flaw demonstrates a failure in the kernel memory management subsystem's privilege enforcement mechanisms, where applications should be restricted from accessing memory areas designated for system operations or other processes.
The technical implementation of this vulnerability involves improper validation of memory access requests within the iOS kernel space. When an application attempts to read or write to memory locations that should be restricted, the system's memory protection units fail to properly validate these access attempts. This could occur through various attack vectors including buffer overflows, use-after-free conditions, or direct memory manipulation techniques that exploit the insufficient validation checks. The vulnerability is particularly concerning because it operates at a low-level system component where proper access controls should be strictly enforced, making it a prime target for advanced persistent threats and privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attack scenarios. An attacker with malicious application capabilities could leverage this flaw to extract sensitive kernel data, process memory contents, or system configuration information that would normally be protected from unauthorized access. This exposure could facilitate further exploitation attempts including credential theft, system state manipulation, or the discovery of additional vulnerabilities within the operating system. The security implications are significant as this weakness could be combined with other exploits to achieve complete system compromise, making it a high-priority vulnerability for remediation.
The fix implemented in iOS 14.6 and iPadOS 14.6 addresses the root cause through enhanced memory access validation checks that enforce stricter boundary controls within the kernel space. These improvements typically involve strengthening the memory management unit's validation routines, implementing more robust privilege level verification, and adding additional layers of access control enforcement. The mitigation strategy focuses on ensuring that all memory access requests undergo comprehensive validation before being granted, with particular attention to preventing unauthorized access to restricted memory regions. This aligns with security best practices outlined in the common weakness enumeration framework under CWE-20, which addresses improper input validation as a fundamental security weakness. Organizations should prioritize deployment of these updates to protect against potential exploitation attempts that could leverage this vulnerability for system compromise.
The remediation approach demonstrates adherence to defensive programming principles and proper access control implementation as recommended by various cybersecurity frameworks including the mitre attack framework where such vulnerabilities might be categorized under privilege escalation or information disclosure tactics. The fix represents a classic case of strengthening kernel-level security controls to prevent unauthorized memory access patterns that could lead to broader system compromise. Security practitioners should also consider implementing additional monitoring and detection mechanisms to identify potential exploitation attempts, particularly focusing on anomalous memory access patterns that might indicate attempted exploitation of similar vulnerabilities.