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Home » Hacking News » SuSE-SA:2002:027-openssl


by Nikola Strahija on July 30th, 2002 Content of this advisory: 1) security vulnerability resolved: openssl 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

The openssl package provides encryption functions and is used by many
applications on SuSE products.

Several buffer overflows have been discovered in the OpenSSL library
affecting the SSL implementation, as well as a signedness issue
in the ASN.1 decoding routines.

In the SSL library, various blobs of data passed from the client to
the server or vice versa were being copied to local buffers without
checking their size. At least one overflow in the SSLv2 server code can
be exploited by an attacker to gain access to the account under which
the SSL enabled service is running. The other overflows happen in the
SSL client code.
The impact of this bug depends on the service using SSL. When attacking
the Apache HTTP server with mod_ssl enabled, the perpetrator could gain
access to the account "wwwrun". Attacking other services, such as the
OpenLDAP slapd server, could even give the attacker access to the system's
root account.

Temporary workarounds for affected services include to disable the ssl
functionality where this is possible. For ssl-enabled webservers, it is
possible to temporarily disable SSLv2: Edit /etc/httpd/httpd.conf and
add the following line to the mod_ssl configuration group:

SSLProtocols all -SSLv2

This should be considered a temporary workaround only.

Since the SSL client implementation is affected as well, and due to the
potential impact of the ASN.1 signedness issues, we recommend that users
who do not run SSL enabled services upgrade their openssl package as well.
By consequence, we recommend all users to update their openssl package.

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.

After performing the package update, all services using the openssl
libraries must be restarted for the update to become effective.
This can be done by rebooting the server or by individually restarting
the services in question manually. To find out which services use the
openssl libraries, use the command

fuser -v /usr/lib/* /usr/lib/*

The ASN1 parser vulnerability was discovered by Adi Stav and James Yonan
We would like to express our gratitude to the openssl team for
their work on the package and the fix for the vulnerability.

Intel i386 Platform:

source rpm(s):

source rpm(s):

source rpm(s):

source rpm(s):

source rpm(s):

Sparc Platform:

The packages for the Sparc platform are being built by the time of the
writing of this announcement and will be published without any delay.

AXP Alpha Platform:

The packages for the Alpha platform are being built by the time of the
writing of this announcement and will be published without any delay.

PPC Power PC Platform:

source rpm(s):

source rpm(s):

source rpm(s):


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- chfn/util-linux
Linux distributors have published security announcements about password
locking race conditions that lead to a local root vulnerability.
SuSE products are not affected by this weakness because we use the
user/group management utilities from the shadow package. These utilities
are not affected.

- mod_ssl
An off-by-one buffer overflow in the mod_ssl apache module is subject to
an upcoming SuSE Security announcement, following this announcement.
The upcoming announcement also treats a temporary file handling problem
that has been discovered by Markus Meissner and Sebastian Krahmer,
SuSE Security.

- libpng
libpng is a library that provides functions for applications to handle
PNG image files (Portable Network Graphics). An overflow vulnerability
has been found in the libpng library that may make it possible for an
attacker to run arbitrary code or to crash an application that uses
the libpng library if the application in question opens a png image file.
We are in the process of fixing this vulnerability.

- wwwoffle (World Wide Web Offline Explorer)
wwwoffle fails to handle negative Content-Length values correctly.
It is believed that an attacker can exploit this bug to gain remote
access to the system running wwwoffle.
We are working on update packages against this problem.

- mod_php4-4.2*
Security vulnerabilities have been found in php versions 4.2.0 and 4.2.1.
SuSE systems are not affected because these systems use older versions
of the php package.

- The SuSE Linux 6.4 distribution has been announced to be discontinued
in June. We have now moved the update directories for all architectures
to the discontinued directory on our ftp server to indicate that no more
updates will be made for this distribution.


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:

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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