CVE-2016-4655 in iOS
Summary
by MITRE
The kernel in Apple iOS before 9.3.5 allows attackers to obtain sensitive information from memory via a crafted app.
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Analysis
by VulDB Data Team • 01/29/2025
The vulnerability identified as CVE-2016-4655 represents a critical information disclosure flaw within Apple iOS kernel components affecting versions prior to 9.3.5. This issue stems from inadequate memory management controls that permit malicious applications to access kernel memory spaces that should remain protected from user-level processes. The vulnerability operates at the core of the operating system's security architecture where kernel memory regions containing sensitive data are not properly isolated from application execution environments. Attackers can exploit this weakness through a specially crafted application that leverages specific kernel APIs or memory access patterns to read data from restricted memory locations.
The technical implementation of this vulnerability involves a memory corruption issue that allows privilege escalation from user space to kernel space. Specifically, the flaw manifests when kernel memory is accessed through improper validation of user-supplied data structures or when kernel functions do not adequately verify memory boundaries during data processing operations. This type of vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-20, which covers improper input validation. The kernel's memory management subsystem fails to properly enforce access controls, creating pathways for unauthorized data extraction. The vulnerability can be exploited through various kernel interfaces that handle memory allocation, deallocation, or data transfer operations, particularly those involving buffer management and memory mapping functions.
The operational impact of CVE-2016-4655 extends beyond simple information disclosure, as attackers can extract sensitive system information including cryptographic keys, user credentials, and system configuration data that could be leveraged for further attacks. This vulnerability enables attackers to gain insights into the kernel's internal state, potentially revealing information about memory layout, process structures, and security mechanisms. The extracted data could facilitate more sophisticated attacks such as privilege escalation, system compromise, or targeted attacks against specific users or applications. Security researchers have noted that this vulnerability could be particularly dangerous when combined with other exploits in a multi-stage attack approach, allowing adversaries to build more comprehensive attack chains. The impact affects all iOS devices running versions before 9.3.5, including iPhones, iPads, and iPod touches, making it a widespread concern for enterprise and individual users alike.
Mitigation strategies for this vulnerability require immediate system updates to iOS 9.3.5 or later versions, as Apple released patches specifically addressing the memory management flaws in the kernel. Organizations should implement comprehensive patch management protocols to ensure all iOS devices are updated promptly, particularly in enterprise environments where device security is paramount. Additional protective measures include implementing mobile device management solutions that can enforce security policies, monitoring for suspicious application behavior, and conducting regular security assessments of iOS environments. The vulnerability demonstrates the importance of kernel-level security controls and proper memory isolation mechanisms, aligning with ATT&CK technique T1055 for privilege escalation and T1005 for data from local system. Network security teams should also monitor for potential exploitation attempts and consider implementing application whitelisting policies to prevent malicious apps from being installed on iOS devices.