CVE-2015-5842 in Watch
Summary
by MITRE
XNU in the kernel in Apple iOS before 9 does not properly initialize an unspecified data structure, which allows local users to obtain sensitive memory-layout information via unknown vectors.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2015-5842 resides within the XNU kernel of Apple iOS versions prior to 9.0, representing a critical information disclosure flaw that stems from improper initialization of an unspecified data structure. This weakness manifests as a failure in the kernel's memory management subsystem to properly establish memory layout parameters during the initialization phase of certain kernel components. The vulnerability's impact extends beyond simple data exposure, as it provides attackers with sensitive memory-layout information that can be leveraged for more sophisticated exploitation techniques. The unspecified nature of the affected data structure suggests this issue involves fundamental kernel memory management mechanisms that are critical to the operating system's security architecture. The vulnerability's classification aligns with CWE-457 which describes "Use of Uninitialized Variable" and represents a fundamental flaw in the kernel's initialization process that violates proper memory safety practices. This type of information disclosure vulnerability is particularly dangerous because it provides attackers with insights into the kernel's memory layout, which can be used to bypass security mechanisms such as address space layout randomization and other exploit mitigations.
The operational impact of this vulnerability in iOS versions before 9.0 creates a significant risk for local attackers who can exploit the uninitialized data structure to gather sensitive memory information. This information disclosure can be leveraged to understand kernel memory organization, which serves as a foundation for more advanced exploitation techniques. The unspecified vectors through which this information is obtained suggest that the vulnerability may be triggered through multiple pathways within the kernel's operational environment, potentially including system calls, memory allocation routines, or other kernel interfaces. Attackers can utilize this memory layout information to craft more effective buffer overflow exploits, return-oriented programming attacks, or other memory corruption techniques that rely on precise knowledge of kernel memory structures. The vulnerability's presence in the XNU kernel specifically affects the core operating system functionality and can potentially compromise the entire system security posture. This type of vulnerability is categorized under the ATT&CK framework's information gathering techniques, where adversaries collect system information to plan subsequent attacks.
The exploitation of CVE-2015-5842 requires local access to the target system, making it a privilege escalation vulnerability that can be particularly dangerous in environments where local user access is possible. The vulnerability's impact on memory layout information can be leveraged to defeat modern exploit mitigations such as kernel address space layout randomization, stack canaries, and other security features that rely on unpredictable memory addresses. This information disclosure can be particularly problematic in mobile environments where the kernel's memory management is critical to device security. The vulnerability represents a failure in the kernel's initialization process that violates fundamental security principles and can be exploited to understand system internals that should remain hidden from local users. The implications extend to the broader security model of iOS, as proper kernel initialization is essential for maintaining the system's security boundaries and preventing unauthorized access to sensitive kernel memory regions. Security researchers have noted that such uninitialized variable vulnerabilities often serve as stepping stones to more serious exploits, as they provide the foundational knowledge required for successful attack planning and execution. The vulnerability demonstrates the critical importance of proper initialization practices in kernel code and highlights the need for comprehensive security testing of core operating system components.