CVE-2018-4283 in macOS
Summary
by MITRE
An out-of-bounds read issue existed that led to the disclosure of kernel memory. This was addressed with improved input validation. This issue affected versions prior to macOS High Sierra 10.13.6.
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Analysis
by VulDB Data Team • 03/01/2020
The vulnerability identified as CVE-2018-4283 represents a critical out-of-bounds read flaw within the macOS kernel that exposed sensitive memory contents to unauthorized processes. This issue specifically impacted systems running versions prior to macOS High Sierra 10.13.6, where the kernel's input validation mechanisms failed to properly sanitize user-supplied data before processing. The flaw originated from insufficient bounds checking in kernel-level code that handled certain system calls or memory operations, creating a pathway for malicious applications to read arbitrary kernel memory locations through crafted inputs.
The technical implementation of this vulnerability falls under CWE-129, which describes improper validation of array indices, and more specifically aligns with CWE-125, indicating out-of-bounds read conditions. The root cause stems from inadequate input validation where kernel functions failed to verify that data pointers or array indices remained within acceptable bounds before accessing memory regions. This type of vulnerability allows attackers to potentially extract confidential information such as cryptographic keys, passwords, or other sensitive kernel data that could be used for privilege escalation or further exploitation. The vulnerability operates at the kernel level, making it particularly dangerous as it bypasses standard user-space protections and can provide attackers with direct access to system internals.
The operational impact of CVE-2018-4283 extends beyond simple information disclosure, as the leaked kernel memory could contain critical system data that enables sophisticated attacks. Attackers could leverage this information to understand kernel memory layout, identify security mechanisms, and potentially craft more effective exploits targeting other vulnerabilities. The vulnerability's exploitation requires minimal privileges since it operates within the kernel context, making it particularly concerning for attackers seeking to escalate privileges or gain persistent access to affected systems. The issue directly violates the principle of least privilege and undermines the kernel's memory protection mechanisms that are fundamental to operating system security.
Mitigation strategies for this vulnerability primarily involve updating to macOS High Sierra 10.13.6 or later versions where Apple implemented enhanced input validation measures to prevent the out-of-bounds read conditions. System administrators should prioritize patching affected systems immediately, as the vulnerability exists in the kernel itself and provides attackers with direct access to system memory. Additional protective measures include implementing kernel memory protection features such as stack canaries, address space layout randomization, and kernel address space layout randomization to make exploitation more difficult. Organizations should also monitor for signs of exploitation through system logs and network traffic analysis, as the memory disclosure could be used as a stepping stone for more advanced attacks. The remediation process should include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing applications while maintaining the security improvements. This vulnerability demonstrates the importance of robust input validation in kernel code and aligns with ATT&CK technique T1068, which covers exploit for privilege escalation through kernel vulnerabilities.