Vulnerability Note VU#464662

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

Overview

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

I. Description

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.

II. Impact

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.

III. Solution

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:

<http://docs.info.apple.com/article.html?artnum=300770>

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.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Apple Computer Inc.	Vulnerable	27-Jan-2005

References

http://docs.info.apple.com/article.html?artnum=300770
http://secunia.com/advisories/14005/

Credit

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

Date Public:	2005-01-25
Date First Published:	2005-01-31
Date Last Updated:	2005-01-31
CERT Advisory:
CVE-ID(s):	CAN-2005-0127
NVD-ID(s):	CAN-2005-0127
US-CERT Technical Alerts:
Metric:	2.81
Document Revision:	11

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