[UNIX] Apple Mac OS X mount_smbfs Stack Based Buffer Overflow Vulnerability

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Apple Mac OS X mount_smbfs Stack Based Buffer Overflow Vulnerability
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SUMMARY

The
<http://developer.apple.com/documentation/Darwin/Reference/ManPages/man8/mount_smbfs.8.html> mount_smbfs utility is "used to mount a remote SMB share locally. It is installed set-uid root, so as to allow unprivileged users to mount shares, and is present in a default installation on both the Server and Desktop versions of Mac OS X". Local exploitation of a stack based buffer overflow vulnerability in Apple Inc.'s Mac OS X mount_smbfs utility could allow an attacker to execute arbitrary code with root privileges.

DETAILS

Vulnerable Systems:
* Mac OS X version 10.4.10

The vulnerability exists in a portion of code responsible for parsing
command line arguments. When processing the -W option, which is used to
specify a workgroup name, the option's argument is copied into a fixed
sized stack buffer without any checks on its length. This leads to a
trivially exploitable stack based buffer overflow.

Analysis:
Exploitation of this vulnerability results in the execution of arbitrary
code with root privileges. In order to exploit this vulnerability, an
attacker must have execute permission for the set-uid root mount_smbfs
binary.

Workaround:
Removing the set-uid bit from the mount_smbfs binary will prevent
exploitation. However, non-root users will be unable to use the program.

Vendor response:
Apple addressed this vulnerability within their Mac OS X 2007-009 security
update. More information is available at the following URL.
<http://docs.info.apple.com/article.html?artnum=307179>

http://docs.info.apple.com/article.html?artnum=307179

CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3876>
CVE-2007-3876

Disclosure Timeline:
07/16/2007 - Initial vendor notification
07/17/2007 - Initial vendor response
12/17/2007 - Coordinated public disclosure

ADDITIONAL INFORMATION

The information has been provided by iDefense Labs.
The original article can be found at:
<http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=633>

http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=633

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