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Home » Hacking News » SuSE SA:2003:036: pam_smb remote privilege escalation

SuSE SA:2003:036: pam_smb remote privilege escalation

by Nikola Strahija on September 3rd, 2003 The PAM module (and server) pam_smb allows users of Linux systems to be authenticated by querying an NT server. A bug in the authentication code of pam_smb allows a remote attacker to gain access to a system using pam_smb by issuing a too long password string.

SuSE Security Announcement

Package: pam_smb
Announcement-ID: SuSE-SA:2003:036
Date: Wednesday, Sep 3nd 2003 16:40 MEST
Affected products: 7.2, 7.3, 8.0, 8.1, 8.2
SuSE Linux Database Server,
SuSE eMail Server III, 3.1
SuSE Linux Enterprise Server 7, 8
SuSE Linux Firewall on CD/Admin host
SuSE Linux Connectivity Server
SuSE Linux Office Server
Vulnerability Type: remote privilege escalation
Severity (1-10): 6
SuSE default package: no
Cross References:

Content of this advisory:
1) security vulnerability resolved: buffer overflow
problem description, discussion, solution and upgrade information
2) pending vulnerabilities, solutions, workarounds:
- gdm2
- whois
- node
- postgresql
- gkrellm
3) standard appendix (further information)


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

The PAM module (and server) pam_smb allows users of Linux systems to
be authenticated by querying an NT server.
Dave Airlie informed us about a bug in the
authentication code of pam_smb that allows a remote attacker to gain
access to a system using pam_smb by issuing a too long password string.

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.

Intel i386 Platform:

patch rpm(s):
source rpm(s):

patch rpm(s):
source rpm(s):

patch rpm(s):
source rpm(s):

source rpm(s):

source rpm(s):

Sparc Platform:

source rpm(s):

PPC Power PC Platform:

source rpm(s):


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- gdm2
Due to a bug in GDM it is possible for local users to read any text
file on a system by creating a symlink from ~/.xsession-errors.
Updated packages will be available on our FTP servers soon.

- whois
The client tool whois is vulnerable to several buffer overflows
while processing its command-line arguments. In conjunction with using
untrusted data from remote sources as input, like using whois in a CGI
script and so on, this buffer overflows may be abused to compromise
a system.
New whois packages are built and will be released at the usual
locations as soon as quality assurance is passed.

- node
The simple hamradio front-end node is vulnerable to buffer overflows
and format-string bugs.
New packages will be available soon.

- postgresql
The SQL database server postgresql of version 7.3.x prior 7.3.4 is
vulnerable to buffer overflow attacks.
New packages will be available soon.

- gkrellm
The server component of the gkrellm monitoring package is
vulnerable to a buffer overflow.
News 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
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.
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 .

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

[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:

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.

Type Bits/KeyID Date User ID
pub 2048R/3D25D3D9 1999-03-06 SuSE Security Team
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key

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