SuSE Security Announcement: man
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From: Roman Drahtmueller <firstname.lastname@example.org>
Subject: [suse-security-announce] SuSE Security Announcement: man (SuSE-SA:2001:019)
Date: Tue, 29 May 2001 20:46:20 +0200 (MEST)
SuSE Security Announcement
Date: Tuesday, May 29th 2001 20:30 MEST
Affected SuSE versions: 6.0, 6.1, 6.2, 6.3, 6.4, 7.0, 7.1
Vulnerability Type: local privilege escalation
Severity (1-10): 4
SuSE default package: yes
Other affected systems: most linux systems shipping the mandb package
Content of this advisory:
1) security vulnerability resolved: man
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
Two vulnerabilities have been found in the man package that is installed
by default in all SuSE Linux distributions. The first error is a format
string bug in the error handling routine of the man command that can
allow a local attacker to gain the privileges of the user "man" on SuSE
Linux systems (the man command in /usr/bin is installed setuid man).
After getting write access to the /usr/bin/man binary, an attacker can
place a cuckook's egg into the executable, waiting for root to view
The second problem is a segmentation fault that can be caused by the
options "-S ::: foo" to the man command. On other Linux distributions,
this problem has been found exploitable. On SuSE and Debian systems, the
code responsible for the bug is different from the one found in other
distributions and is not exploitable. We consider the existence of this
bug a beauty flaw that will be fixed in future releases of the SuSE Linux
distribution, but the fix was not included in the man packages that can
be found on our ftp server.
Since the error() format string bug was discovered earlier than we
announced that the SuSE Linux distributions 6.0, 6.1 and 6.2 will be
discontinued, we also provide fixed packages for the said distributions
for the i386 Intel architecture. We strongly encourage our usership to
upgrade their systems to a newer distribution.
Both bugs are fixed in the upcoming release of SuSE Linux 7.2.
A temporary workaround (as discussed in earlier SuSE security
announcements) is to remove the setuid-bit of the /usr/bin/man file.
This will cause errors to be printed when viewing a manpage, because
the formatted manpages can't be saved to the /var/cache/man directories
any longer. The sideeffects of this workaround are of mostly cosmetical
nature on fast hardware.
If you changed the file modes of the man command binary using the command
chmod 755 /usr/bin/man
, then please also change the occurrences of the same path in the files
/etc/permissions*, provided you have set the variable CHECK_PERMISSIONS
to "set" in /etc/rc.config.
Download the update package from locations described below and check the
authenticity of the rpm package file using a method as described in
section 3) of this security announcement.
Use the command `rpm -Uhv file.rpm' to apply the update.
In some rare cases, the older man package contains files that conflict
with the new version. This should not be considered a problem in this
particular case of the man packge; use the options "--nodeps --force"
i386 Intel Platform:
AXP Alpha Platform:
PPC Power PC Platform:
2) Pending vulnerabilities in SuSE Distributions and Workarounds:
Netscape before Version 4.77 contains a bug that allows a remote attacker
contained in a viewed page. This code can be executed.
Update packages for the SuSE Linux distributions 6.3, 6.4, 7.0 and 7.1
can be found on our ftp server at
The packages are gpg-signed. See the section above about downloading
and verifying rpm packages.
The complexity of the netscape browser suggests by nature that more
security related problems will be found, we will not issue a dedicated
security announcement for the netscape package any more. Security-
inclined users may please see the future security announcements in
section 2) for information about security related problems with the
The gpg update package that can be found on our ftp server upgrade your
installation of gpg to the version 1.0.5. We have experienced stability
problems when the turkish locale was used.
We recommened our users to wait for the official SuSE Security
Announcement about gpg/gnupg before performing the upgrade since we
expect more changes to the package.
Most of the supported distributions have pine update packages in the
update area of the ftp server that update the pine package to version
4.33. Many vulnerabilities have been found in versions before 4.33,
and it is recommended to perform the upgrade.
Please note that not all packages have been built yet. See the update
directory for your distribution (like i386/update/7.0/n1) for pine-4.33
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). We are working on update
packages that fix the problem.
Insecure temporary file handling is the cause for a new samba version
2.0.9 that can be found as rpm packages in the n1/ directory of your
distribution. It is recommended to install the update package if your
users have local shell access to your samba server (this bug is not
We are currently investigating some oddity in the behaviour of the
samba package and will send a security announcement as soon as we
have clarified the problems. The problems were present in earlier
releases/versions of the samba package as well. By consequence, the
installation of the update package is of low risk for the functionality
of your system.
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
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 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.
Roman Drahtmueller <firstname.lastname@example.org>
| Roman Drahtmüller // "The best way to pay for a |
SuSE GmbH - Security Phone: // lovely moment is to enjoy it."
| Nürnberg, Germany +49-911-740530 // - Richard Bach |
The information in this advisory may be distributed or reproduced,
provided that the advisory is not modified in any way.
SuSE GmbH makes no warranties of any kind whatsoever with respect
to the information contained in this security advisory.