__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Snort RPC Preprocessing Vulnerability [Internet Security Systems Security Brief] March 3, 2003 18:00 GMT Number N-049 [Revised 5 March, 2003] ______________________________________________________________________________ PROBLEM: A buffer overflow flaw exists in the Snort RPC preprocessing code that is enabled by default. PLATFORM: Snort 1.8 (July 2001) up to and including Snort-Current (March 3, 2003 1pm ET) DAMAGE: A remote attacker may exploit the buffer overflow condition to run arbitrary code on a Snort sensor with the privileges of the Snort IDS process (typically root). SOLUTION: Upgrade to Snort 1.9.1. If you are unable to upgrade, comment out the line in your snort.conf file that begins: preprocessor rpc_decode and replace it with: #preprocessor rpc_decode ______________________________________________________________________________ VULNERABILITY The risk is HIGH. This vulnerability is especially dangerous ASSESSMENT: because it is not necessary to establish an actual connection to a RPC portmapper service to exploit this vulnerability. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-049.shtml ORIGINAL BULLETIN: http://bvlive01.iss.net/issEn/delivery/xforce/alertdetail.jsp?oid=21951 ADDITIONAL LINKS: http://www.snort.org/ ______________________________________________________________________________ [***** Start Internet Security Systems Security Brief *****] Internet Security Systems Security Brief March 3, 2003 Snort RPC Preprocessing Vulnerability Synopsis: ISS X-Force has discovered a remotely exploitable buffer overflow condition in Snort. Snort is an open source intrusion detection system. A buffer overflow flaw exists in Snort RPC preprocessing code that is vulnerable to attack. Impact: Remote attackers may exploit the buffer overflow condition to run arbitrary code on a Snort sensor with the privileges of the Snort IDS process, which typically runs as the superuser. The vulnerable preprocessor is enabled by default. It is not necessary to establish an actual connection to a RPC portmapper service to exploit this vulnerability. Snort may be installed by default on some commercially available network-security appliances. Remote attackers can exploit this vulnerability by directing the exploit towards any host on any network monitored by the Snort intrusion detection system. A successful attack can either crash the Snort sensor, or lead to complete remote compromise. Affected Versions: Snort 1.8 (July 2001) up to and including Snort-Current (March 3, 2003 1pm ET) For the complete ISS X-Force Security Advisory, please visit: http://bvlive01.iss.net/issEn/delivery/xforce/alertdetail.jsp?oid=21951 ______ About Internet Security Systems (ISS) Founded in 1994, Internet Security Systems (ISS) (Nasdaq: ISSX) is a pioneer and world leader in software and services that protect critical online resources from an ever-changing spectrum of threats and misuse. Internet Security Systems is headquartered in Atlanta, GA, with additional operations throughout the Americas, Asia, Australia, Europe and the Middle East. Copyright (c) 2003 Internet Security Systems, Inc. All rights reserved worldwide. Permission is hereby granted for the electronic redistribution of this document. It is not to be edited or altered in any way without the express written consent of the Internet Security Systems X-Force. If you wish to reprint the whole or any part of this document in any other medium excluding electronic media, please email xforce@iss.net for permission. Disclaimer: The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (Internet Security Systems X-Force) be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information. X-Force PGP Key available on MIT's PGP key server and PGP.com's key server, as well as at http://www.iss.net/security_center/sensitive.php Please send suggestions, updates, and comments to: X-Force xforce@iss.net of Internet Security Systems, Inc. [***** End Internet Security Systems Security Brief *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Internet Security Systems (X-Force) and SNORT organization 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. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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