CVE-2016-4717 in macOS
Summary
by MITRE
The File Bookmark component in Apple OS X before 10.12 mishandles scoped-bookmark file descriptors, which allows attackers to cause a denial of service via a crafted app.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-4717 resides within the File Bookmark component of Apple's macOS operating system versions prior to 10.12. This flaw represents a critical security issue that affects how the system handles scoped-bookmark file descriptors, creating potential pathways for malicious actors to exploit the operating system's file access mechanisms. The vulnerability specifically targets the way macOS manages file system access controls and bookmarking functionality, which are integral components for maintaining secure file operations across the system.
The technical flaw manifests in the improper handling of scoped-bookmark file descriptors, which are used by macOS applications to maintain persistent access to files across system restarts and other operations. When an application creates a scoped bookmark, it generates a file descriptor that should be properly validated and managed by the operating system. However, the vulnerability allows attackers to craft malicious applications that manipulate these descriptors in ways that cause the system to malfunction or crash. This improper handling occurs at the kernel level where file descriptor validation should occur, but instead leads to memory corruption or resource exhaustion conditions that result in system instability.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged by attackers to disrupt normal system operations and potentially gain unauthorized access to sensitive data. When exploited, the vulnerability causes the system to become unresponsive or crash entirely, effectively creating a denial of service condition that prevents legitimate users from accessing their files and applications. The attack vector requires only a crafted application that can be executed by a user, making it particularly dangerous as it can be delivered through various means including malicious email attachments, compromised websites, or social engineering campaigns.
From a security standards perspective, this vulnerability maps to CWE-121, which describes the weakness of stack-based buffer overflow, and also aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The flaw demonstrates poor input validation and improper resource management practices that violate fundamental security principles. Organizations should note that this vulnerability affects a core operating system component that is essential for file system operations, making it a high-priority target for remediation efforts. The vulnerability's impact is particularly severe because it can be triggered through legitimate application execution, making detection and prevention challenging. Security professionals should implement immediate mitigation strategies including system updates to macOS 10.12 or later versions, along with monitoring for suspicious application behavior and file access patterns that might indicate exploitation attempts.
The remediation approach for CVE-2016-4717 requires immediate deployment of the official macOS security updates provided by Apple. System administrators should prioritize patch management procedures to ensure all affected systems receive the necessary security patches. Additional protective measures include implementing application whitelisting policies, monitoring for unusual file system access patterns, and maintaining comprehensive system logs that can help detect exploitation attempts. Organizations should also consider network segmentation and access controls to limit the potential impact of successful exploitation attempts. The vulnerability serves as a reminder of the importance of proper input validation and resource management in operating system components, particularly those handling file system access controls and security mechanisms.