[UNIX] SNMPd Log Files Buffer Overflow Problem

From: support@securiteam.com
Date: 08/11/01 

From: support@securiteam.com
To: list@securiteam.com
Subject: [UNIX] SNMPd Log Files Buffer Overflow Problem
Message-Id: <20010811102639.75A31138BF@mail.der-keiler.de>
Date: Sat, 11 Aug 2001 12:26:39 +0200 (CEST)

The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com

  SNMPd Log Files Buffer Overflow Problem
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SUMMARY

 <http://sourceforge.net/projects/net-snmp/> net-snmp provides tools and
libraries relating to the Simple Network Management Protocol including: An
extensible agent, an SNMP library, tools to request or set information
from SNMP agents, tools to generate and handle SNMP traps, etc.

SNMPd suffers from a buffer overflow vulnerability that allows a local
attacker to cause the program to execute arbitrary code.

DETAILS

Vulnerable systems:
ucd-snmp version 4.2.1 (Official)

Immune systems:
ucd-snmp version 4.2.1 (CVS)

SNMPd provides a parameter named '-l', this specifies which file should be
used for logging. If SNMPd is lunched with an overly long argument (-l) of
the sort: " -l AAAAAAAA....[455 chars]" the program will crash. This
buffer overflow would allow a local attacker to execute arbitrary code.

Vulnerable code:
On line 306 of snmpd.c, they have:
char logfile[SNMP_MAXBUF_SMALL];

Where SNMP_MAXBUF_SMALL is defined in tools.h as a 512 buffer.

And last but not least, on line 321 of snmpd.c:
strcpy(logfile, LOGFILE);

Solution:
An update has been posted to the CVS. Download the latest version from:
 <http://sourceforge.net/projects/net-snmp/>
http://sourceforge.net/projects/net-snmp/

ADDITIONAL INFORMATION

The information has been provided by <mailto:security@eds.com.ar>
SECURITY and <mailto:methodic@libpcap.net> Tony Lambiris.

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