Users login

Create an account »


Users login

Home » Hacking News » SuSE-SA:2002:031- glibc

SuSE-SA:2002:031- glibc

by Nikola Strahija on September 5th, 2002 Content of this advisory: 1) security vulnerability resolved: glibc problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds: - ethereal 3) standard appendix (further information)

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

An integer overflow has been discovered in the xdr_array() function,
contained in the Sun Microsystems RPC/XDR library, which is part of
the glibc library package on all SuSE products. This overflow allows
a remote attacker to overflow a buffer, leading to remote execution of
arbitrary code supplied by the attacker.

There is no temporary workaround for this security problem other than
disabling all RPC based server and client programs. The permanent
solution is to update the glibc packages with the update packages
listed below.

Notes, Special installation instructions:

* The update packages for the SuSE Linux distributions 7.0 and 7.1
have not been built yet. The packages for these distributions will
be published in approximately two weeks (mid September) from now.

* The names of both the source RPM as well as the binary RPM (sub-)
packages have changed between different SuSE Linux products.
dist | source-RPM | shared libs | static libs,header| profiling
7.0 libc shlibs libc libd
all SuSE products after and including SuSE Linux 7.1
glibc glibc glibc-devel glibc-profile

Find out which of the four packages are installed on your system
according to the package names in the table. Use the command
rpm -q name_of_package
to query the package database for each name.
If you have your package list, download the packages that you need
from the URLs as listed below. Verify their integrity and authenticity
following the guidelines as described in section 3) of this security

The shared libraries package of the glibc is the most sensitive
part of a running Linux system, and modifications to it should be
handled with special care. During the update of the shlibs/glibc
package, runtime-linking the shared libraries is likely to fail for
processes that execute a new binary with the execve(2) system call.
Therefore, we recommend to bring a system to single user mode
("init S") to perform the package update. If this is not applicable
for operational reasons, a system receiving the update should be kept
as quiet as possible (no shell scripts of any kind, no cron jobs, no
incoming email).

* After performing the update, you should run the following command
on your system:
ldconfig will rebuild the runtime linker cache. If you use YOU
(Yast2 Online Update), the ldconfig command will be executed
automatically at the end of the update.

The shared libraries that were installed on the system before the
update have been removed from the filesystem, but they are still
in use by the running applications. Therefore, the diskspace as well
as the memory will not be freed until the last process that uses
these files exits. We recommend to reboot the system to workaround
this problem.

Listed below you find the URLs for the update packages for the SuSE Linux
products. We only list the packages that are relevant for the security
Our maintenance customers are being notified individually. The packages
are being offered to install from the maintenance web.

Intel i386 Platform:

source rpm(s):

source rpm(s):

source rpm(s):

Sparc Platform:

source rpm(s):

AXP Alpha Platform:

- no new packages -

PPC Power PC Platform:

source rpm(s):


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- ethereal
Multiple overflows and other security related problems have been found
in ethereal, a network traffic analyzer program. We have provided update
packages on our ftp server that upgrade the ethereal package to the
latest version 0.9.6. A backport of the security fixes to the versions
supplied in the released SuSE Linux products does not seem feasible.
We will not release an own announcement for this specific problem.

- postgresql
A buffer overflow has been found in the postgresql database management
system. We are about to prepare update packages for this vulnerability.

- openldap2
Andrew McCall reported a problem within the openldap2 package which could
lead to a denial of service attack against the slapd server. This problem
has been fixed. New openldap2 packages will soon be available.


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 .

[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:

Newsletter signup

Signup to our monthly newsletter and stay in touch with IT news!

Free E-books

We've got ebooks! But they're not online. :( Please give us a few days to bring downloads back.


Have something to say or just wanna drop us a line? Please keep this in mind: to spam, we reply with spam.

Contact us »