Public Vulnerability Reports

Apple Mac OS X Mach Port Inheritance Privilege Escalation Vulnerability



Mach ports are used to provide inter-process communication (IPC) facilities on Mac OS X. More information can be found on the vendor's site at the following URL.


Local exploitation of an access validation vulnerability in Apple Inc.'s Mac OS X could allow an attacker to execute arbitrary code with root privileges.

When executing a setuid-root binary, the Mach kernel does not reset the current thread Mach port, or the current thread Mach Exception Port. By first creating and obtaining write access to a Mach port, and then executing a set-uid root binary, an attacker can write arbitrary data into the address space of the process running as root. This leads to arbitrary code execution in the privileged process.


Successful exploitation of this vulnerability results in the execution of arbitrary code with root privileges. All an attacker needs is a setuid-root binary and permission to execute it. In a default install, there are numerous binaries that meet these requirements.


iDefense has confirmed the existence of this vulnerability in Mac OS X version 10.4.10, both Server and Workstation. Previous versions may also be affected.


iDefense is currently unaware of any workaround for this issue.


Apple addressed this vulnerability within their Mac OS X 2007-008 security update. More information is available at the following URL.


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-3749 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


09/07/2007 Initial vendor notification
09/10/2007 Initial vendor response
11/14/2007 Coordinated public disclosure


The discoverer of this vulnerability wishes to remain anonymous.

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Copyright © 2007 Verisign, Inc.

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