CVE-2016-1720 in iOS
Summary
by MITRE
IOKit in Apple iOS before 9.2.1, OS X before 10.11.3, and tvOS before 9.1.1 allows local users to gain privileges or cause a denial of service (memory corruption) via unspecified vectors.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability identified as CVE-2016-1720 resides within the IOKit framework of Apple's operating systems, representing a critical privilege escalation and denial of service flaw affecting iOS versions prior to 9.2.1, macOS versions before 10.11.3, and tvOS versions before 9.1.1. This issue demonstrates the inherent risks associated with kernel-level subsystems that handle hardware device interactions and system resource management. IOKit serves as the foundational framework for device driver management and hardware abstraction within Apple's ecosystem, making it a prime target for attackers seeking to elevate their privileges or disrupt system operations. The vulnerability stems from unspecified vectors within the kernel's memory management and device driver handling mechanisms, creating potential pathways for malicious code execution at the highest privilege levels.
The technical nature of this vulnerability involves memory corruption issues that can be exploited by local attackers to either escalate privileges or cause system crashes. Memory corruption vulnerabilities typically arise from improper bounds checking, use-after-free conditions, or buffer overflow scenarios within kernel code. In the context of IOKit, such flaws often manifest when device drivers fail to properly validate input parameters or when memory allocation and deallocation routines contain race conditions or improper access controls. The unspecified nature of the attack vectors suggests multiple potential entry points within the framework, making the vulnerability particularly concerning as it could be exploited through various pathways including malformed device communications, improper memory management during driver initialization, or insecure inter-process communications between kernel components and user-space applications.
The operational impact of CVE-2016-1720 extends beyond simple denial of service scenarios to encompass full system compromise capabilities for local attackers. Privilege escalation vulnerabilities within kernel frameworks represent the most severe class of security flaws as they allow attackers to execute code with the highest system privileges, effectively bypassing all user-level security controls. This vulnerability could enable attackers to install persistent backdoors, modify system files, access encrypted data, or exfiltrate sensitive information from compromised systems. The memory corruption aspect also creates potential for system instability, where successful exploitation could result in kernel panics, system crashes, or unpredictable behavior that could be leveraged for further attacks. The local nature of the vulnerability means that attackers must already have access to the target system, but this access requirement does not necessarily limit the potential damage, as the privilege escalation could be used to establish persistent access or to escalate from limited user accounts to administrative privileges.
Mitigation strategies for CVE-2016-1720 focus primarily on applying the official security patches released by Apple, which address the underlying memory corruption issues within the IOKit framework. System administrators should prioritize immediate deployment of the relevant updates for iOS 9.2.1, macOS 10.11.3, and tvOS 9.1.1, as these releases contain the necessary code modifications to prevent exploitation. Organizations should also implement monitoring for unusual system behavior or kernel-level activity that might indicate exploitation attempts, particularly around device driver interactions and memory management operations. Network segmentation and privilege separation can help limit the potential impact of successful exploitation, while regular security assessments should verify that systems remain patched and that no unauthorized modifications have occurred. This vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may also relate to CWE-122 for heap-based buffer overflows, both of which are common categories for kernel-level memory corruption vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and may involve multiple tactics including persistence and defense evasion, as attackers could leverage the elevated privileges to maintain access or conceal their activities within the compromised system.