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Home » Hacking News » NetBSD 2003-009: sendmail buffer overflow

NetBSD 2003-009: sendmail buffer overflow

by Nikola Strahija on April 6th, 2003 A buffer overflow vulnerability has been found in sendmail versions 8.12.8 and below which, if exploited, can allow remote attackers to issue Denial of Service attacks or execution of arbitrary code.


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NetBSD Security Advisory 2003-009
=================================

Topic: sendmail buffer overrun in prescan() address parser

Version: NetBSD-current: source prior to Mar 30, 2003
NetBSD 1.6: affected
NetBSD-1.5.3: affected
NetBSD-1.5.2: affected
NetBSD-1.5.1: affected
NetBSD-1.5: affected
pkgsrc: prior to sendmail-8.12.9

Severity: Remote root compromise

Fixed: NetBSD-current: March 30, 2003
NetBSD-1.6 branch: March 30, 2003 (1.6.1 will include the fix)
NetBSD-1.5 branch: April 1, 2003
pkgsrc: sendmail-8.12.9 corrects this issue


Abstract
========

- From the CERT advisory:

There is a remotely exploitable vulnerability in sendmail that
could allow an attacker to gain control of a vulnerable sendmail
server. Address parsing code in sendmail does not adequately check
the length of email addresses. An email message with a specially
crafted address could trigger a stack overflow. This vulnerability
was discovered by Michal Zalewski.

This vulnerability is different than the one described in CA-2003-07.

It is a different vulnerability than NetBSD SA2003-002.


Technical Details
=================

http://www.cert.org/advisories/CA-2003-12.html


Solutions and Workarounds
=========================


We advise sites running sendmail to upgrade as soon as possible. If upgrading
is impossible at this time, we recommend you turn off the sendmail service.

To determine if sendmail is running on your system, issue the command:

# /etc/rc.d/sendmail status

To stop currently running sendmail processes, issue the command:

# /etc/rc.d/sendmail stop

To ensure sendmail does not start after the next reboot, issue the command:

# echo "sendmail=NO" >>/etc/rc.conf.d/sendmail

To allow sendmail to start once upgraded, remove the sendmail=NO line
from the end of /etc/rc.conf.d/sendmail.


The following instructions describe how to upgrade your sendmail
binaries by updating your source tree and rebuilding and
installing a new version of sendmail.

* NetBSD-current:

Systems running NetBSD-current dated from before 2003-03-30
should be upgraded to NetBSD-current dated 2003-03-31 or later.

The following directories need to be updated from the
netbsd-current CVS branch (aka HEAD):
gnu/dist/sendmail/sendmail

To update from CVS, re-build, and re-install sendmail:
# cd src
# cvs update -d -P gnu/dist/sendmail/sendmail
# cd gnu/usr.sbin/sendmail

# make USETOOLS=no cleandir dependall
# make USETOOLS=no install


* NetBSD 1.6:

The binary distribution of NetBSD 1.6 is vulnerable.

Systems running NetBSD 1.6 sources dated from before
2003-03-30 should be upgraded from NetBSD 1.6 sources dated
2003-03-31 or later.

NetBSD 1.6.1 will include the fix.

The following directories need to be updated from the
netbsd-1-6 CVS branch:
gnu/dist/sendmail/sendmail

To update from CVS, re-build, and re-install sendmail:

# cd src
# cvs update -d -P -r netbsd-1-6 gnu/dist/sendmail/sendmail
# cd gnu/usr.sbin/sendmail

# make USETOOLS=no cleandir dependall
# make USETOOLS=no install




* NetBSD 1.5, 1.5.1, 1.5.2, 1.5.3:

The binary distribution of NetBSD 1.5.3 is vulnerable.

Systems running NetBSD 1.5, 1.5.1, 1.5.2, or 1.5.3 sources dated
from before 2003-04-01 should be upgraded from NetBSD 1.5.*
sources dated 2003-04-02 or later.

The following directories need to be updated from the
netbsd-1-5 CVS branch:
gnu/dist/sendmail/sendmail

To update from CVS, re-build, and re-install sendmail:

# cd src
# cvs update -d -P -r netbsd-1-5 gnu/dist/sendmail/sendmail
# cd gnu/usr.sbin/sendmail

# make cleandir dependall
# make install



Thanks To
=========


Michal Zalewski and CERT for notification.

Andrew Brown for patches.


Revision History
================

2003-04-04 Initial release


More Information
================

Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at
ftp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2003-009.txt.asc

Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.ORG/ and http://www.NetBSD.ORG/Security/.


Copyright 2003, The NetBSD Foundation, Inc. All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2003-009.txt,v 1.2 2003/04/04 05:52:33 david Exp $

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