CVE-2018-4171 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.5 is affected. The issue involves the "Bluetooth" component. It allows attackers to obtain sensitive kernel memory-layout information via a crafted app that leverages device properties.
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Analysis
by VulDB Data Team • 03/19/2023
The vulnerability identified as CVE-2018-4171 represents a significant information disclosure flaw within Apple's macOS operating system affecting versions prior to 10.13.5. This security weakness resides within the Bluetooth component of the system, specifically targeting the kernel memory layout information that should remain protected from unauthorized access. The flaw enables malicious actors to extract sensitive kernel memory information through a specially crafted application that exploits device properties within the Bluetooth subsystem. This type of vulnerability falls under the category of information disclosure attacks where attackers can gain insights into the internal structure of the kernel memory, potentially aiding in more sophisticated exploitation techniques.
The technical nature of this vulnerability stems from insufficient input validation and memory protection mechanisms within the Bluetooth driver component of macOS. When a crafted application interacts with Bluetooth device properties, it can trigger a condition where kernel memory addresses and layout information become accessible to user-space processes. This occurs due to improper boundary checks and memory access controls that fail to properly isolate kernel memory from user applications. The vulnerability specifically exploits the interaction between the Bluetooth subsystem and the kernel's memory management functions, allowing unauthorized data extraction through seemingly benign device property queries. This weakness aligns with CWE-200, which categorizes information exposure vulnerabilities where sensitive information is unintentionally made available to unauthorized actors.
The operational impact of CVE-2018-4171 extends beyond simple information disclosure, as the leaked kernel memory layout information can significantly aid attackers in developing more advanced exploitation techniques. Knowledge of kernel memory addresses and structure layouts enables attackers to craft more precise buffer overflow exploits, bypass memory protection mechanisms such as stack canaries, and potentially circumvent kernel address space layout randomization. This information can be particularly valuable when combined with other vulnerabilities, as it provides attackers with detailed insights into the target system's memory organization. The vulnerability affects macOS systems before version 10.13.5, representing a substantial attack surface that could be exploited in targeted campaigns against users running outdated operating systems.
Mitigation strategies for this vulnerability primarily focus on immediate system updates to macOS 10.13.5 or later versions where Apple has implemented proper memory protection and input validation controls within the Bluetooth subsystem. System administrators should prioritize patching affected systems and ensure that all macOS installations are updated to versions containing the necessary security fixes. Additional protective measures include implementing network segmentation to limit Bluetooth device access, disabling unnecessary Bluetooth functionality on systems where it is not required, and monitoring for suspicious Bluetooth-related activities that might indicate exploitation attempts. Organizations should also consider deploying endpoint protection solutions that can detect anomalous Bluetooth device property access patterns and provide real-time monitoring of kernel memory access behaviors. From an ATT&CK framework perspective, this vulnerability maps to techniques involving information gathering and privilege escalation, as the leaked information can be used to facilitate more sophisticated attacks targeting the kernel directly.
The vulnerability demonstrates the critical importance of proper memory management and input validation in operating system components, particularly those handling hardware interactions such as Bluetooth drivers. Apple's response through the security update addresses the root cause by strengthening memory access controls and implementing proper validation of device property queries within the kernel space. This remediation approach aligns with security best practices for preventing information disclosure vulnerabilities and ensures that kernel memory remains properly isolated from user-space applications. The fix likely involves enhanced bounds checking, improved memory protection mechanisms, and stricter validation of Bluetooth device property access requests to prevent unauthorized memory layout information disclosure. Organizations should maintain updated inventory of their macOS systems and verify that all devices have been patched to prevent exploitation of this and similar information disclosure vulnerabilities.