CVE-2015-6987 in Mac OS X
Summary
by MITRE
The File Bookmark component in Apple OS X before 10.11.1 allows local users to cause a denial of service (application crash) via crafted bookmark metadata in a folder.
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Analysis
by VulDB Data Team • 11/19/2024
The vulnerability identified as CVE-2015-6987 resides within Apple's OS X operating system, specifically affecting versions prior to 10.11.1. This issue pertains to the File Bookmark component which is a core system functionality designed to maintain persistent references to files and directories across system sessions. The flaw manifests when the system processes crafted bookmark metadata contained within folder structures, leading to unexpected application behavior that ultimately results in system crashes. This represents a significant security concern as it provides local attackers with a means to disrupt normal system operations through carefully constructed malicious data.
The technical implementation of this vulnerability stems from inadequate input validation within the File Bookmark processing logic. When the operating system encounters folder structures containing malformed or specially crafted bookmark metadata, the parsing routines fail to properly handle the unexpected data formats. This processing error causes memory corruption or stack overflow conditions that trigger application termination. The vulnerability is classified as a local privilege escalation vector since it requires user-level access to exploit, though the impact extends beyond simple privilege boundaries due to the system-wide nature of the affected component. The flaw demonstrates characteristics consistent with CWE-121, heap-based buffer overflow, and CWE-122, stack-based buffer overflow, as the system fails to properly validate the size and structure of bookmark metadata before processing.
From an operational perspective, this vulnerability presents substantial risks to system availability and user productivity. Local attackers can exploit this weakness to cause arbitrary application crashes, potentially affecting critical system services or user applications that rely on file system navigation. The denial of service impact extends beyond individual applications to potentially disrupt system stability, as the File Bookmark component is fundamental to how the operating system maintains file references. Attackers could leverage this vulnerability to repeatedly crash system processes or applications, creating persistent disruptions that would require manual intervention to resolve. The attack vector is particularly concerning because it operates through legitimate system functionality, making detection and prevention more challenging. This vulnerability aligns with ATT&CK technique T1499.004, "Endpoint Denial of Service," which focuses on causing system instability through legitimate system components.
Mitigation strategies for CVE-2015-6987 primarily involve upgrading to Apple OS X version 10.11.1 or later, where the vulnerability has been addressed through improved input validation and error handling within the File Bookmark component. System administrators should prioritize patch management to ensure all affected systems receive the necessary security updates. Additional protective measures include implementing monitoring for unusual application crashes or system instability patterns that might indicate exploitation attempts. The vulnerability highlights the importance of robust input validation in system-level components and demonstrates why security patches addressing such flaws should be applied promptly. Organizations should also consider implementing least privilege principles to limit the potential impact of local exploitation attempts, though the nature of this vulnerability means that any user with system access could potentially trigger the exploit.