Date: Fri, 3 Aug 2001 19:33:59 +0200 (CEST)
From: Thomas Biege <email@example.com>
Subject: SuSE Security Announcement: xmcd (SuSE-SA:2001:025)
SuSE Security Announcement
Date: Friday, Aug 3rd 2001 18:30 MEST
Affected SuSE versions: (6.0, 6.1, 6.2,) 6.3, 6.4, 7.0, 7.1, 7.2
Vulnerability Type: local privilege escalation
Severity (1-10): 4
SuSE default package: no
Other affected systems: yes
Content of this advisory:
1) security vulnerability resolved: yes
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
Cda, a setuid commandline part of xmcd, a X11/Motif audio CD player by
Ti Kan <firstname.lastname@example.org>, was found vulnerable by a link attack and some
These bugs could be exploited by an adversary, who has access to the
system, to overwrite files or gain higher privileges.
As a temporary fix, just remove the setuid bit from cda:
/bin/chmod 755 /usr/X11R6/bin/cda
or let just trusted users execute cda:
/bin/chown root.trusted /usr/X11R6/bin/cda
/bin/chmod 4750 /usr/X11R6/bin/cda
Don't forget to add these changes to your /etc/permissions.local file
Users of SuSE 7.2 with permissions.secure or permissions.paranoid
activated are safe, because setuid is already removed.
Thanks to Paul Starzetz <email@example.com>, who reportes the link attack
and to Ti Kan <firstname.lastname@example.org>, the author of xmcd, for his fast response
New RPMs can be found at the following places.
i386 Intel Platform:
AXP Alpha Platform:
PPC PowerPC Platform:
2) Pending vulnerabilities in SuSE Distributions and Workarounds:
Currently we check are checking the dependencies of openssl to other
dynamic or static linked applications on SuSE Linux. An announcement
will be released soon.
email@example.com has found an exploitable buffer overflow bug in
the dsh program from the dqs package on SuSE Linux distributions.
To workaround the problem, do "chmod -s /usr/bin/dsh" and change the
files /etc/permissions* to reflect the change. If you do not need the
dqs package, then deinstall it (rpm -e dqs).
Packages for most of the supported SuSE Linux distributions are
available at the usual location ftp://ftp.suse.com/pub/suse//
for download and installation/update. Do not forget to change the files
/etc/permissions* to remove the suid-bit from the dsh program. Please
note that we will not issue a dedicated security announcement for this
Paul Starzetz discovered a security weakness in the setuid root program
/usr/share/pcp/bin/pmpost. The common library in pcp trusts the
environment that has been supplied by the user, regardless of privileged
execution or not. By consequence, a user can specify the configuration
file and therefore write to files owned by root. The problem is not based
on insecurely following symlinks as stated by Paul Starzetz.
The pcp package is not installed by default in SuSE Linux distributions.
We have provided update packages for the SuSE Linux distributions version
7.1 and 7.2 that remove the setuid bit from the pmpost binary. Versions
before SuSE-7.1 were not affected because the setuid bit was not set.
We thank Keith Owens and Mark Goodwin from Silicon Graphics for responding
quickly and for publishing a new version of the pcp package which will
be included in future releases of the SuSE Linux distribution. For more
information see the /usr/share/doc/packages/pcp directory of your SuSE
Linux installation after installing the update package, or go to
obtained from http://oss.sgi.com/projects/pcp/download .
Please note that there will not be a dedicated security announcement
for this specific bug.
- fetchmail (fetchml)
New fetchmail packages are available on the ftp server. The packages
cure a buffer overflow that can be exploited by sending a victim a
specially designed email, waiting for the victim's fetchmail program
to pick up the email. We are preparing a security announcement for this
update packages for the openssh package after (and including) SuSE-6.4
are available on our ftp servers ftp ftp.suse.de (for < 7.1) or
ftp ftp.suse.com (for >= 7.1). We are currently checking for a non-security
related irregularity in sshd's behaviour under faulty setup conditions.
SuSE Linux distributions do not contain the exim Mail Transport Agent
(See http://www.exim.org/ for details) and are therefore not susceptible
to the recently found security-related bugs.
SuSE Linux distributions do not contain the webmin administration
web frontend (See http://www.webmin.org/ for details) and are therefore
not vulnerable to the recently found security-related problems in the
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 firstname.lastname@example.org),
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
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 <file.rpm>
to verify the signature of the package, where <file.rpm> is the
filename of the rpm package that you have downloaded. Of course,
package authenticity verification can only target an uninstalled rpm
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@example.com" upon installation or upgrade, provided that
the package gpg is installed. The file containing the public key
is placed at the toplevel 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
- general/linux/SuSE security discussion.
All SuSE security announcements are sent to this list.
To subscribe, send an email to
- SuSE's announce-only mailing list.
Only SuSE's security annoucements 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 <firstname.lastname@example.org>.
The <email@example.com> 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 cleartext signature shows proof of the
authenticity of the text.
SuSE GmbH makes no warranties of any kind whatsoever with respect
to the information contained in this security advisory.
Thomas Biege, SuSE GmbH, Schanzaeckerstr. 10, 90443 Nuernberg
E@mail: firstname.lastname@example.org Function: Security Support & Auditing
"lynx -source http://www.suse.de/~thomas/contact/thomas.asc | pgp -fka"
Key fingerprint = 51 AD B9 C7 34 FC F2 54 01 4A 1C D4 66 64 09 84