Apple Mac OS X vulnerable to buffer overflow via vpnd daemon

Overview

Apple Mac OS X contains a buffer overflow in vpnd that could allow a local, authenticated attacker to execute arbitrary code with root privileges.

Description

Mac OS X includes a VPN server called vpnd, which is installed setuid root by default. vpnd fails to validate the length of the Server_id parameter. The Server_id setting may be configured from the command line by using the -i option. Server_id is referenced by the com.apple.RemoteAccessServers.plist file in the /Library/Preferences/SystemConfiguration directory to load the appropriate configuration file. Using a specially crafted Server_id parameter, an authenticated local attacker could execute arbitrary code with privileges of the vpnd process.

Note that com.apple.RemoteAccessServers.plist is only present by default on Mac OS X Server. On a standard Mac OS X install, the file must be created manually or by using the graphical network configuration tools.

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Impact

A local, authenticated attacker could execute arbitrary code with root privileges.

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Solution

Apply a patch
Apple advises all users to apply Apple Security Update 2005-005, which fixes this flaw and other critical security flaws.

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Workarounds

Disallow non-root access to**vpnd**

Clear the execute bit of the vpnd binary for non-root users.

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Vendor Information

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Apple Computer Inc. __ Affected

Updated: May 17, 2005

Status

Affected

Vendor Statement

We have not received a statement from the vendor.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

Apple advises all users to apply Apple Security Update 2005-005.

If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23706838 Feedback>).

CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://docs.info.apple.com/article.html?artnum=301528&gt;
• <http://secunia.com/advisories/15227/&gt;
• http://www.idefense.com/application/poi/display?id=240&type=vulnerabilities
• <http://www.securityfocus.org/bid/13488&gt;
• <http://www.securitytracker.com/alerts/2005/May/1013887.html&gt;
• <http://www.osvdb.org/displayvuln.php?osvdb_id=16085&gt;

Acknowledgements

This vulnerability was reported by Jason Aras.

This document was written by Will Dormann, based on the information provided in the iDEFENSE Security Advisory 05.04.05 .

Other Information

CVE IDs:	CVE-2005-1343
Severity Metric:	9.38 Date Public: