CVE-2021-1852 in iOS
Summary
by MITRE • 09/08/2021
An out-of-bounds read was addressed with improved input validation. This issue is fixed in iOS 14.5 and iPadOS 14.5. A local user may be able to read kernel memory.
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Analysis
by VulDB Data Team • 09/08/2021
This vulnerability represents a critical out-of-bounds read flaw that emerged within the kernel execution context of ios and ipad os operating systems. The issue stems from insufficient input validation mechanisms that fail to properly sanitize or verify data boundaries before processing memory operations. When malicious input reaches kernel space, the system attempts to access memory locations beyond allocated buffers, potentially exposing sensitive kernel memory contents to unauthorized access. The vulnerability specifically affects devices running ios 14.4 and earlier versions, as well as ipad os 14.4 and earlier releases where the security patch has not been applied. This type of flaw falls under the common weakness enumeration category CWE-129 which encompasses improper validation of array index bounds, while also aligning with ATT&CK technique T1068 which covers local privilege escalation through kernel exploits.
The operational impact of this vulnerability extends beyond simple information disclosure as it provides a potential attack vector for local users to extract kernel memory contents. While the exploit requires local system access, once achieved it could reveal sensitive information including cryptographic keys, credential storage locations, or other confidential data structures within kernel memory. Attackers could leverage this information to craft more sophisticated attacks or bypass security mechanisms that depend on kernel-level protections. The flaw essentially creates a window for unauthorized memory inspection that could compromise the entire system integrity. Security researchers have identified that such out-of-bounds read vulnerabilities often serve as stepping stones for more severe exploits, making early remediation critical for maintaining system security posture.
The fix implemented by apple addresses this vulnerability through enhanced input validation procedures that properly check array bounds and buffer limits before kernel memory operations occur. This remediation aligns with established security practices for preventing buffer overflow conditions and their associated memory access violations. The update specifically targets the kernel execution path where the improper input handling occurs, ensuring that all incoming data undergoes proper sanitization before being processed in kernel space. Organizations should prioritize deployment of ios 14.5 and ipad os 14.5 updates across all affected devices to eliminate this risk vector. System administrators should also conduct vulnerability assessments to identify any remaining legacy systems that may be running unsupported versions of these operating systems, as they remain susceptible to exploitation through similar memory access flaws.
The broader implications of this vulnerability highlight the ongoing challenges in kernel-level security where even minor input validation gaps can create significant attack surfaces. This issue demonstrates how seemingly small flaws in memory management can have cascading effects on overall system security, particularly when they enable unauthorized memory inspection capabilities. The remediation process underscores the importance of maintaining up-to-date operating system versions and implementing comprehensive patch management procedures to protect against known vulnerabilities that could be exploited by determined attackers with local access privileges. Security professionals should monitor for similar patterns in other kernel components and ensure that input validation controls are consistently applied throughout all system memory management operations.