__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Apple Mac OS X AppleFileServer Authentication Vulnerability [US-CERT VU#648406] May 10, 2004 21:00 GMT Number O-139 ______________________________________________________________________________ PROBLEM: The AppleFileServer provides Apple Filing Protocol (AFP) services for clients and servers to share files over the network. A buffer overflow vulnerability in the way the AppleFileServer handles certain authentication requests has been found. PLATFORM: Mac OS X DAMAGE: A remote attacker could overflow a buffer, gain root privileges, and execute arbitrary commands on the system. SOLUTION: Check for appropriate patches from the Apple Security Advisory web site. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. A remote attacker could gain root ASSESSMENT: (administrator) privileges. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/O-139.shtml ORIGINAL BULLETIN: http://www.kb.cert.org/vuls/id/648406 ADDITIONAL LINKS: ISS X-Force: http://xforce.iss.net/xforce/xfdb/16049 Apple: http://docs.info.apple.com/article.html?artnum=61798 CVE/CAN: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CAN-2004-0430 ______________________________________________________________________________ [***** Start US-CERT VU#648406 *****] Vulnerability Note VU#648406 Apple Mac OS X AppleFileServer fails to properly handle certain authentication requests Overview There is a buffer overflow vulnerability in the way Apple's AppleFileServer handles certain authentication requests. This vulnerability could allow an unauthenticated, remote attacker to execute arbitrary code. I. Description The AppleFileServer provides Apple Filing Protocol (AFP) services for clients and servers. This protocol allows users to share files over the network. By default the AFP service is not enabled. There is a buffer overflow vulnerability in the way the AppleFileServer handles certain authentication requests. By supplying a specially crafted PathName argument during authentication, an unauthenticated, remote attacker could execute arbitrary code. According to the @stake advisory: There is a pre-authentication, remotely exploitable stack buffer overflow that allows an attacker to obtain administrative privileges. The overflow occurs when parsing the PathName argument from LoginExt packet requesting authentication using the Cleartext Password User Authentication Method (UAM). The PathName argument is encoded as one-byte specifying the string type, two-bytes specifying the string length, and finally the string itself. A string of type AFPName (0x3) that is longer than the length declared in the packet will overflow the fixed-size stack buffer. II. Impact An unauthenticated, remote attacker could execute arbitrary code. III. Solution Apply Patch Apple has issued an advisory to address this issue. For further details, please see the Apple Security Advisory (Security Update 2004-05-03). Disable AppleFileServer Until a patch can be applied, you may wish to disable the AppleFileServer. Systems Affected Vendor Status Date Updated Apple Computer Inc. Vulnerable 7-May-2004 References http://www.atstake.com/research/advisories/2004/a050304-1.txt http://docs.info.apple.com/article.html?artnum=61798 http://secunia.com/advisories/11539/ http://www.securiteam.com/securitynews/5QP0115CUO.html http://www.securitytracker.com/alerts/2004/May/1010039.html2 Credit This vulnerability was reported by Dave G. of @stake. This document was written by Damon Morda based on information in the @stake advisory. Other Information Date Public 05/03/2004 Date First Published 05/07/2004 10:48:38 AM Date Last Updated 05/07/2004 CERT Advisory CVE Name CAN-2004-0430 Metric 27.42 Document Revision 24 If you have feedback, comments, or additional information about this vulnerability, please send us email. [***** End US-CERT VU#648406 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of US-CERT and ISS X-Force for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. 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