N-049: Snort RPC Preprocessing Vulnerability

N-049: Snort RPC Preprocessing Vulnerability Privacy and Legal Notice INFORMATION BULLETIN N-049: Snort RPC Preprocessing Vulnerability [Internet Security Systems Security Brief] March 3, 2003 18:00 GMT
Revised [5 March, 2003]


PROBLEM:	A buffer overflow flaw exists in the Snort RPC preprocessing code that is enabled by default.
AFFECTED SOFTWARE:	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 ASSESSMENT:	The risk is HIGH. This vulnerability is especially dangerous 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 ISS and SNORT for information contained in this bulletin.

DOE-CIRC can be contacted at:

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