CVE-2017-6990 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.12.5 is affected. The issue involves the "HFS" component. It allows attackers to bypass intended memory-read restrictions via a crafted app.
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Analysis
by VulDB Data Team • 09/02/2024
The vulnerability identified as CVE-2017-6990 represents a significant security flaw within Apple's macOS operating system affecting versions prior to 10.12.5. This issue resides within the HFS (Hierarchical File System) component which serves as the primary file system implementation for macOS environments. The flaw manifests as a memory access restriction bypass that can be exploited through carefully crafted applications, potentially allowing unauthorized access to memory regions that should otherwise be protected from user-level applications. The vulnerability specifically targets the memory management controls that govern how applications interact with system memory, creating a pathway for malicious code to circumvent normal security boundaries.
The technical nature of this vulnerability stems from improper validation of memory access requests within the HFS subsystem. When a crafted application attempts to access memory regions through the file system interface, the system fails to properly enforce memory read restrictions that are typically enforced by the kernel's memory management subsystem. This weakness allows an attacker to craft applications that can probe and access memory locations that should be restricted to system processes or privileged operations. The flaw operates at the kernel level where file system operations interface with memory management, creating a vector through which attackers can escalate privileges or access sensitive data. This type of vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions that can lead to information disclosure or privilege escalation.
The operational impact of CVE-2017-6990 extends beyond simple memory access violations as it provides attackers with potential pathways for privilege escalation and information disclosure. An attacker who successfully exploits this vulnerability could gain access to kernel memory regions that contain sensitive information such as encryption keys, user credentials, or system configuration data. The attack vector requires the victim to execute a specially crafted application, making social engineering or supply chain compromise potential delivery methods. This vulnerability aligns with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and represents a classic example of how file system vulnerabilities can be leveraged to bypass operating system security controls. The impact is particularly concerning in enterprise environments where macOS systems may be running outdated versions that have not received the necessary security patches.
Mitigation strategies for CVE-2017-6990 primarily focus on immediate system updates and administrative controls. The most effective remediation involves upgrading affected macOS systems to version 10.12.5 or later where Apple has implemented proper memory access validation within the HFS subsystem. System administrators should prioritize patch management to ensure all macOS devices receive the necessary security updates. Additional protective measures include implementing application whitelisting policies that restrict execution of unsigned or untrusted applications, monitoring for unusual file system access patterns, and maintaining up-to-date endpoint protection solutions. Organizations should also consider network segmentation to limit the potential impact of successful exploitation attempts and implement security awareness training to reduce the risk of social engineering attacks that could deliver malicious payloads. The vulnerability demonstrates the critical importance of keeping operating systems updated and the potential consequences of running outdated software versions in enterprise security environments.