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Home » Hacking News » SuSE Security Announcement: sendmail

SuSE Security Announcement: sendmail

by Nikola Strahija on March 3rd, 2003 A remotely exploitable buffer overflow has been found in all versions of sendmail that come with SuSE products. These versions include sendmail-8.11 and sendmail-8.12 releases. sendmail is the MTA subsystem that is installed by default on all SuSE products up to and including SuSE Linux 8.0 and the SuSE Linux Enterprise Server 7.


Package: sendmail, sendmail-tls
Announcement-ID: SuSE-SA:2003:013
Date: Monday, March 3rd 2003, 18:10 MET
Affected products: 7.1, 7.2, 7.3, 8.0, 8.1
SuSE Linux Database Server,
SuSE Linux Enterprise Server 7, 8
SuSE Linux Firewall on CD/Admin host
SuSE Linux Connectivity Server
SuSE Linux Office Server
Vulnerability Type: local privilege escalation
Severity (1-10): 7
SuSE default package: yes (until SuSE Linux 8.0 and SLES7)
Cross References: http://www.cert.org/advisories/CA-2003-07.html

Content of this advisory:
1) security vulnerability resolved: sendmail
problem description, discussion, solution and upgrade information
2) pending vulnerabilities, solutions, workarounds:
- vnc
- w3m
3) standard appendix (further information)

______________________________________________________________________________

1) problem description, brief discussion, solution, upgrade information

sendmail is the most widely used mail transport agent (MTA) in the
internet. A remotely exploitable buffer overflow has been found in all
versions of sendmail that come with SuSE products. These versions include
sendmail-8.11 and sendmail-8.12 releases. sendmail is the MTA subsystem
that is installed by default on all SuSE products up to and including
SuSE Linux 8.0 and the SuSE Linux Enterprise Server 7.

The vulnerability is triggered by an email message sent through the
sendmail MTA subsystem. In that respect, it is different from commonly
known bugs that occur in the context of an open TCP connection. By
consequence, the vulnerability also exists if email messages get forwarded
over a relay that itself does not run a vulnerable MTA. This specific
detail and the wide distribution of sendmail in the internet causes this
vulnerability to be considered an error of major severity.

The buffer overflow happens on the heap and is known to be exploitable.
As of the writing of this announcement, there is no exploit known to exist
in the public. Since there is no known workaround for this vulnerability
other than using a different MTA, it is strongly recommended to install
the update packages as offered at the locations as listed below.

We would like to express our gratitude to Eric Allman for notifying
SuSE Security of the problem. The vulnerability was discovered by
ISS Internet Security Systems, inc.

Please download the update package for your distribution and verify its
integrity by the methods listed in section 3) of this announcement.
Then, install the package using the command "rpm -Fhv file.rpm" to apply
the update.
Our maintenance customers are being notified individually. The packages
are being offered to install from the maintenance web.

SPECIAL INSTALL INSTRUCTIONS:
==============================
After performing the update, it is necessary to restart all running
instances of sendmail using the command "rcsendmail restart" as root.



Intel i386 Platform:

SuSE-8.1:
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-91.i586.rpm
0f3d981ad8e9be64bc70aff474ce303c
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-devel-8.12.6-91.i586.rpm
afe98a29de75ecd362fad5b02a922856
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-91.i586.patch.rpm
ebd8f188748812aff2830b23de6f34b3
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-devel-8.12.6-91.i586.patch.rpm
09ff6834c369051d165d78f01a44d684
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/sendmail-8.12.6-91.src.rpm
50e471df3a90ce4b54b2c5ca3fbc081e

SuSE-8.0:
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-72.i386.rpm
09e0a8ed5b189c7c819d3d38f74a07e1
ftp://ftp.suse.com/pub/suse/i386/update/8.0/d4/sendmail-devel-8.12.3-72.i386.rpm
72a8c31090299df6b7bd52ea38c31c2b
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-72.i386.patch.rpm
905b39525ecd0506892b442a204b7aa3
ftp://ftp.suse.com/pub/suse/i386/update/8.0/d4/sendmail-devel-8.12.3-72.i386.patch.rpm
a03e4a221c1fb8f2387dc133ada9e604
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sendmail-8.12.3-72.src.rpm
6e3106de72c4605d379dc2133adba97b

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/i386/update/7.3/n1/sendmail-8.11.6-162.i386.rpm
9d04ffb6a8d6f1fe6e2efe217de69ad7
ftp://ftp.suse.com/pub/suse/i386/update/7.3/sec2/sendmail-tls-8.11.6-164.i386.rpm
ebf8d1b2ef233a68b0326e6ce6974994
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/sendmail-8.11.6-162.src.rpm
aebf9a30089a13717928e9ba5309a6ed
ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/sendmail-tls-8.11.6-164.src.rpm
371e39b10ee7d4c255e96e935c473aa8

SuSE-7.2:
ftp://ftp.suse.com/pub/suse/i386/update/7.2/n1/sendmail-8.11.3-106.i386.rpm
dbff6db47875bc00a95409cba9498c49
ftp://ftp.suse.com/pub/suse/i386/update/7.2/sec2/sendmail-tls-8.11.3-110.i386.rpm
7c7af39c8179219f6302707ab67bacea
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sendmail-8.11.3-106.src.rpm
85ff9f88013f6f0b23ed8fb15704bc82
ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/sendmail-tls-8.11.3-110.src.rpm
7502589ff50b89f86398571c5686c23c

SuSE-7.1:
ftp://ftp.suse.com/pub/suse/i386/update/7.1/n1/sendmail-8.11.2-44.i386.rpm
701f6c5d9748e0b9cd5606cdaaa84cd8
ftp://ftp.suse.com/pub/suse/i386/update/7.1/sec2/sendmail-tls-8.11.2-45.i386.rpm
1583015b284c5166c9bd862c3e24bf14
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sendmail-8.11.2-44.src.rpm
b51e8383dc11ca9be65e05ee4209f740
ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/sendmail-tls-8.11.2-45.src.rpm
3de4e382d512f6175cc5050d393d76a0



Sparc Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/n1/sendmail-8.11.6-63.sparc.rpm
0f70b263b09c319dcf698786b14de86f
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/sec2/sendmail-tls-8.11.6-63.sparc.rpm
e7a3f0c6fadcbaedc9736c2a7a08aa5f
source rpm(s):
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/sendmail-8.11.6-63.src.rpm
1a455df96d094008fcd7bc96f49ab938
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/sendmail-tls-8.11.6-63.src.rpm
20d1fdca82189f4492a1dd28ba0d7e92




AXP Alpha Platform:

SuSE-7.1:
ftp://ftp.suse.com/pub/suse/axp/update/7.1/n1/sendmail-8.11.2-30.alpha.rpm
dfdd75f7e970002742135a5f48c9be71
ftp://ftp.suse.com/pub/suse/axp/update/7.1/sec2/sendmail-tls-8.11.2-37.alpha.rpm
ff6d0889f04eff5564c9e498954f9a85
source rpm(s):
ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/sendmail-8.11.2-30.src.rpm
92bd9eee0d1b9eac76f4835f4f20dfe2
ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/sendmail-tls-8.11.2-37.src.rpm
a5e9e67a860bfd6b873cb9d95134405b



PPC Power PC Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/n1/sendmail-8.11.6-120.ppc.rpm
ef7b092c43dddc3fcdfa45946df42232
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/sec2/sendmail-tls-8.11.6-119.ppc.rpm
927355dfa069ad1f032a1036ad65fb2c
source rpm(s):
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/sendmail-8.11.6-120.src.rpm
35c672698ccaa213c6e42b2888ac24ad
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/sendmail-tls-8.11.6-119.src.rpm
c1ff2ba2174ed85c47fad4149e82e564

SuSE-7.1:
ftp://ftp.suse.com/pub/suse/ppc/update/7.1/n1/sendmail-8.11.2-33.ppc.rpm
d703b68846212626fdf1e1d3e15c733f
ftp://ftp.suse.com/pub/suse/ppc/update/7.1/sec2/sendmail-tls-8.11.2-36.ppc.rpm
d98905aaa881fec5684f32ff1d4927de
source rpm(s):
ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sendmail-8.11.2-33.src.rpm
b582465c56651e15153ad5a0239cea6a
ftp://ftp.suse.com/pub/suse/ppc/update/7.1/zq1/sendmail-tls-8.11.2-36.src.rpm
f1ef3e9c0f346cf4e7c4f9f70b049878



______________________________________________________________________________

2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- vnc
VNC (Virtual Network Computing) uses a weak cookie generation process
which can be exploited by an attacker to bypass authentication.
New packages are currently being tested and will be available on our
FTP servers soon.

- w3m
The textbased web-browser w3m does not properly escape HTML tags.
A malicious HTML page or img alt attribute may lead to information
leakage. New packages will be available soon.
______________________________________________________________________________

3) standard appendix: authenticity verification, additional information

- Package authenticity verification:

SuSE update packages are available on many mirror ftp servers all over
the world. While this service is being considered valuable and important
to the free and open source software community, many users wish to be
sure about the origin of the package and its content before installing
the package. There are two verification methods that can be used
independently from each other to prove the authenticity of a downloaded
file or rpm package:
1) md5sums as provided in the (cryptographically signed) announcement.
2) using the internal gpg signatures of the rpm package.

1) execute the command
md5sum
after you downloaded the file from a SuSE ftp server or its mirrors.
Then, compare the resulting md5sum with the one that is listed in the
announcement. Since the announcement containing the checksums is
cryptographically signed (usually using the key [email protected]),
the checksums show proof of the authenticity of the package.
We disrecommend to subscribe to security lists which cause the
email message containing the announcement to be modified so that
the signature does not match after transport through the mailing
list software.
Downsides: You must be able to verify the authenticity of the
announcement in the first place. If RPM packages are being rebuilt
and a new version of a package is published on the ftp server, all
md5 sums for the files are useless.

2) rpm package signatures provide an easy way to verify the authenticity
of an rpm package. Use the command
rpm -v --checksig
to verify the signature of the package, where is the
filename of the rpm package that you have downloaded. Of course,
package authenticity verification can only target an un-installed rpm
package file.
Prerequisites:
a) gpg is installed
b) The package is signed using a certain key. The public part of this
key must be installed by the gpg program in the directory
~/.gnupg/ under the user's home directory who performs the
signature verification (usually root). You can import the key
that is used by SuSE in rpm packages for SuSE Linux by saving
this announcement to a file ("announcement.txt") and
running the command (do "su -" to be root):
gpg --batch; gpg < announcement.txt | gpg --import
SuSE Linux distributions version 7.1 and thereafter install the
key "[email protected]" upon installation or upgrade, provided that
the package gpg is installed. The file containing the public key
is placed at the top-level directory of the first CD (pubring.gpg)
and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de .


- SuSE runs two security mailing lists to which any interested party may
subscribe:

[email protected]
- general/linux/SuSE security discussion.
All SuSE security announcements are sent to this list.
To subscribe, send an email to
.

[email protected]
- SuSE's announce-only mailing list.
Only SuSE's security announcements are sent to this list.
To subscribe, send an email to
.

For general information or the frequently asked questions (faq)
send mail to:
or
respectively.

=====================================================================
SuSE's security contact is or .
The public key is listed below.
=====================================================================
______________________________________________________________________________

The information in this advisory may be distributed or reproduced,
provided that the advisory is not modified in any way. In particular,
it is desired that the clear-text signature shows proof of the
authenticity of the text.
SuSE Linux AG makes no warranties of any kind whatsoever with respect
to the information contained in this security advisory.


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