CVE-2015-3767 in Mac OS X
Summary
by MITRE
udf in Apple OS X before 10.10.5 allows local users to gain privileges or cause a denial of service (memory corruption and application crash) via a malformed DMG image.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2015-3767 resides within the Universal Disk Format UDF implementation in Apple macOS operating systems prior to version 10.10.5. This issue represents a critical security flaw that affects the system's handling of DMG (Disk Image) files, which are commonly used for distributing software and data on macOS platforms. The vulnerability stems from insufficient input validation and memory management within the UDF filesystem parser, creating a pathway for malicious actors to exploit the system through crafted disk image files.
Technical exploitation of this vulnerability occurs when a local user presents a malformed DMG image to the operating system for mounting or inspection. The UDF subsystem fails to properly validate the structure and content of these disk images, leading to memory corruption that can be leveraged to execute arbitrary code with elevated privileges or cause system instability through application crashes. The flaw manifests as a buffer overflow or heap corruption condition within the kernel-level filesystem handling code, where the system attempts to parse malformed UDF structures without adequate bounds checking. This type of vulnerability aligns with CWE-121, heap-based buffer overflow, and CWE-125, out-of-bounds read, as the system processes untrusted input without proper validation mechanisms.
The operational impact of CVE-2015-3767 extends beyond simple privilege escalation to encompass potential system compromise and denial of service conditions. An attacker with local access can leverage this vulnerability to elevate their privileges from standard user to root level, effectively bypassing macOS security controls and gaining complete system control. Additionally, the memory corruption can lead to unpredictable application behavior, system crashes, and potential data loss. The vulnerability is particularly concerning because it requires no network connectivity or remote exploitation, making it accessible through local file manipulation or social engineering attacks where users might be tricked into mounting malicious disk images. This aligns with ATT&CK technique T1068, locally installed malicious software, and T1059, command and scripting interpreter, as the attack vector involves local privilege escalation through legitimate system utilities.
Mitigation strategies for this vulnerability primarily focus on immediate system updates and administrative controls. Apple released security patches for macOS 10.10.5 that address the UDF parsing issues through enhanced input validation and memory management routines. Organizations should implement comprehensive patch management protocols to ensure all systems receive the necessary updates promptly. Additional protective measures include restricting user access to disk image mounting capabilities, implementing sandboxing controls for disk image handling applications, and monitoring for suspicious mounting activities. System administrators should also consider deploying automated tools to scan for and block known malicious DMG files, while maintaining regular security audits to identify potential exploitation attempts. The vulnerability demonstrates the importance of robust input validation in kernel-level code and highlights the critical need for thorough security testing of filesystem implementations in operating system components.