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Home » Hacking News » SuSE-SA:2002:045-samba

SuSE-SA:2002:045-samba

by Nikola Strahija on November 24th, 2002 Content of this advisory: 1) security vulnerability resolved: samba problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds 3) standard appendix (further information)


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

Samba developer Steve Langasek found a security problem in samba, the
widely known free implementation of the SMB protocol.

The error consists of a buffer overflow in a commonly used routine
that accepts user input and may write up to 127 bytes past the end of
the buffer allocated with static length, leaving enough room for
an exploit. The resulting vulnerability can be exploited locally
in applications using the pam_smbpass Pluggable Authentication Module
(PAM). It may be possible to exploit this vulnerability remotely,
causing the running smbd to crash or even to execute arbitrary code.

The samba package is installed by default only on the SuSE Linux
Enterprise Server. SuSE Linux products do not have the samba and
samba-client packages installed by default.
The samba packages in SuSE Linux version 7.1 and before are not affected
by this vulnerability.
For the bug to be exploited, your system has to be running the smbd
samba server, or an administrator must have (manually) changed the
configuration of the PAM authentification subsystem to enable the use
of the pam_smbpass module. The samba server process(es) are not activated
automatically after installation (of the package).

The samba subsystem on SuSE products is split into two different
subpackages: samba and smbclnt up to and including SuSE Linux 7.2, on
SuSE Linux 7.3 and newer the package names are samba and samba-client.
To completely remove the vulnerability, you should update all of the
installed packages.

We wish to express our gratitude to the samba development team and
in particular to Steve Langasek and Volker Lendecke who provided the
patches and communicated them to the vendors. Please know that the
samba team will release the new version 2.2.7 of the samba software to
address the security fix at the same time as this announcement gets
published. More information about samba (and the security fix) is
available at http://www.samba.org.

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 successfully installing the update packages, you should restart
the samba server process(es) to make the changes in the system effective.
If you do not have a samba server running on your system, no further
action is required. If you have a samba server running, please run the
following command as root:
rcsmb restart # SuSE Linux, all versions
rcnmb restart # only on SuSE Linux 8.1



Intel i386 Platform:

SuSE-8.1:
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/samba-2.2.5-124.i586.rpm
f0a94ef6cc49165d4dace59caaf359d7
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/samba-client-2.2.5-124.i586.rpm
f694fb4aaabffa98b6a76941cb2c0eaf
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/samba-2.2.5-124.i586.patch.rpm
af43bc1d5dc1b097389933f34ca5a625
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/samba-client-2.2.5-124.i586.patch.rpm
bff278f9366df7efe72fa880c4f7618f
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/samba-2.2.5-124.src.rpm
674adb466663259c2117852b9525a29a

SuSE-8.0:
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n2/samba-2.2.3a-165.i386.rpm
8c7edd09c5acfc269467ecbcdcdfc21c
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/samba-client-2.2.3a-165.i386.rpm
bfc08a1d64f0d85670041c7046d1e775
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n2/samba-2.2.3a-165.i386.patch.rpm
7d08c2c07137d9da0b3d1a301295a084
ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/samba-client-2.2.3a-165.i386.patch.rpm
887230d4ed61bec496dff73c50fa3de0
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/samba-2.2.3a-165.src.rpm
b208c4d5bcceb7f9cc18df75b7831d2d

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/i386/update/7.3/n2/samba-2.2.1a-206.i386.rpm
dc4232333a0babbb257cff346609625f
ftp://ftp.suse.com/pub/suse/i386/update/7.3/n1/samba-client-2.2.1a-206.i386.rpm
163a565a5a0b0320eae6ba1d0ebdfb27
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/samba-2.2.1a-206.src.rpm
6086e3bb296a320c28fced9068c931fc

SuSE-7.2:
ftp://ftp.suse.com/pub/suse/i386/update/7.2/n2/samba-2.2.0a-45.i386.rpm
184b17987ca99325782f4c7f9e04b6a6
ftp://ftp.suse.com/pub/suse/i386/update/7.2/n1/smbclnt-2.2.0a-45.i386.rpm
b9926ade015ccaf271088da246814abb
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/samba-2.2.0a-45.src.rpm
384ec49b0b8a81d8ecf7c84ef0fa2689




Sparc Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/n2/samba-2.2.1a-69.sparc.rpm
61b72787bc8e0b333662962a60bce0c2
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/n1/samba-client-2.2.1a-69.sparc.rpm
6acd0ffd218d721d7c10b17e1194738d
source rpm(s):
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/samba-2.2.1a-69.src.rpm
77f57a3277bb1a270ae79bc94ee28345



PPC Power PC Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/n2/samba-2.2.1a-141.ppc.rpm
d127afabc7d5b764289f9b65ad4c4cd1
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/n1/samba-client-2.2.1a-141.ppc.rpm
894132f3b5041a54ec871d67eef072e5
source rpm(s):
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/zq1/samba-2.2.1a-141.src.rpm
ccff812fdddd3af9d62a399f63e0405e




______________________________________________________________________________

2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- 7.0 update trees
We will move the SuSE Linux 7.0 update tree structure to the
/pub/suse/discontinued/ tree shortly, following the announcement about
discontinued products on Tue, 29 Oct 2002.

______________________________________________________________________________

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.


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