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TUCoPS :: Unix :: General :: n-049.txt
Snort RPC Preprocessing Vulnerability (CIAC N-049)

__________________________________________________________

The U.S. Department of Energy
Computer Incident Advisory Capability
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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/
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[***** 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.

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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