iDefense Security Advisory 11.14.07: Apple Mac OS X Mach Port Inheritance Privilege Escalation Vulnerability
iDefense Security Advisory 11.14.07
http://labs.idefense.com/intelligence/vulnerabilities/
Nov 14, 2007
I. BACKGROUND
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.
http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming/boundaries/chapter_14_section_4.html
II. DESCRIPTION
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.
III. ANALYSIS
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.
IV. DETECTION
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.
V. WORKAROUND
iDefense is currently unaware of any workaround for this issue.
VI. VENDOR RESPONSE
Apple addressed this vulnerability within their Mac OS X 2007-008
security update. More information is available at the following URL.
http://docs.info.apple.com/article.html?artnum=307041
VII. CVE INFORMATION
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 (http://cve.mitre.org/), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
09/07/2007 Initial vendor notification
09/10/2007 Initial vendor response
11/14/2007 Coordinated public disclosure
IX. CREDIT
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright © 2007 iDefense, Inc.
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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
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