search menu icon-carat-right cmu-wordmark

CERT Coordination Center

Apple Mac OS X vulnerable to information disclosure in "Message-ID" header

Vulnerability Note VU#464662

Original Release Date: 2005-01-31 | Last Revised: 2005-01-31


The Mail application supplied with Apple's Mac OS X operating system identifies the system from which any electronic mail is sent.


Mac OS X includes the Mail application for handling electronic mail. This application does include the Media Access Control (MAC) address of a network interface in the Message-ID header, which discloses the system which sent the mail.


This flaw makes it possible to identify the system that has sent a given piece of electronic mail with the Mail application. An intruder may use this information, which is usually transmitted in cleartext and received on a remote system, to deduce a valid MAC address to use on a foreign network in order to gain access. This value may also be used to deduce the sender of anonymized or privatized mail.


Apply a patch

Apple advises all users to apply Apple Security Update 2005-001, as it fixes this flaw and other critical security flaws. More information can be found at:


This patch enables Mail to apply a cryptographic hash function to the GUUID and random data from /dev/random in order to create a Message-ID which does not contain identifying information.

Vendor Information


Apple Computer Inc. Affected

Updated:  January 27, 2005



Vendor Statement

Please see the following link for the statement from Apple Computer Inc.:


Vendor Information

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


US-CERT has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

Group Score Vector



Thanks to Apple Product Security for reporting this vulnerability. Apple, in turn, gives thanks to Carl Purvis for originally reporting this vulnerability.

This document was written by Ken MacInnis.

Other Information

CVE IDs: CVE-2005-0127
Severity Metric: 2.81
Date Public: 2005-01-25
Date First Published: 2005-01-31
Date Last Updated: 2005-01-31 19:48 UTC
Document Revision: 11

Sponsored by CISA.