CVE-2015-3767

Vulnerability

The vulnerability resides in the udf kernel extension in Apple OS X versions prior to 10.10.5. It is triggered when the system mounts a specially crafted DMG image containing a malformed UDF filesystem. The issue leads to memory corruption.

Exploitation

An attacker must have local access to the system and the ability to mount a DMG image (e.g., by inserting a USB drive or downloading a malicious image). No additional authentication is required beyond local user privileges. The attacker crafts a DMG with a malformed UDF structure; upon mounting, the kernel extension processes the malformed data, causing memory corruption.

Impact

Successful exploitation allows the attacker to cause a denial of service (application crash) or potentially escalate privileges to kernel level, gaining full control of the system.

Mitigation

Apple addressed this vulnerability in OS X Yosemite v10.10.5, released on August 13, 2015 [1]. Users should update to that version or later. No workarounds are documented. The vulnerability is not listed on CISA's Known Exploited Vulnerabilities catalog.