From labs-no-reply@idefense.com Wed May 4 12:04:20 2005 From: iDEFENSE Labs To: full-disclosure@lists.grok.org.uk Date: Wed, 4 May 2005 11:56:17 -0400 Subject: [Full-disclosure] iDEFENSE Security Advisory 05.04.05: Apple Mac OS X vpnd Server_id Buffer Overflow Vulnerability Apple Mac OS X vpnd Server_id Buffer Overflow Vulnerability iDEFENSE Security Advisory 05.04.05 www.idefense.com/application/poi/display?id=240&type=vulnerabilities May 04, 2005 I. BACKGROUND Mac OS X is an operating system for the Apple family of microcomputers. More information is available at the following link: http://www.apple.com/macosx/ II. DESCRIPTION Local exploitation of a buffer overflow vulnerability in Apple Computer, Inc.'s Mac OS X allows attackers to execute arbitrary code. vpnd is the system daemon which manages IPSEC or PPTP connections. The vulnerability specifically exists due to insufficient bounds checking on the value given to the Server_id parameter. Server_id may be set from the command line via the -i option. The Server_id is then referenced from the com.apple.RemoteAccessServers.pslist file in the /Library/Preferences/SystemConfiguration directory to load the appropriate configuration profile. Local attackers can supply an overly long Server_id value to overflow the buffer and execute arbitrary code. III. ANALYSIS Successful exploitation of this vulnerability will result in execution of arbitrary code with root privileges. It should be noted that the com.apple.RemoteAccessServers.pslist file is only present by default on Server platforms. On standard OS X installs, the file must be created manually or generated by the graphical network configuration tools in order for vpnd to execute far enough to cause the overflow to occur. IV. DETECTION iDEFENSE has confirmed that Mac OS X 10.3.7 is vulnerable. The vendor has indicated that all versions prior to OS X 10.3.9 are vulnerable. V. WORKAROUND As a workaround solution, remove the executable privilege bit for non-root users from the /usr/sbin/vpnd binary until the vendor releases a patch. VI. VENDOR RESPONSE The vulnerability is addressed in Apple Security Update 2005-005: http://docs.info.apple.com/article.html?artnum=301528 VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2005-1271 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 04/25/2005 Initial vendor notification 04/27/2005 Initial vendor response 05/04/2005 Coordinated public disclosure IX. CREDIT Jason Aras is credited with this vulnerability. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.idefense.com X. LEGAL NOTICES Copyright (c) 2005 iDEFENSE, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDEFENSE. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email customerservice@idefense.com for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/