SuSE: 'zlib/libz' Data corruption vulnerability, Part II
Summary
______________________________________________________________________________
SuSE Security Announcement
Package: libz/zlib
Announcement-ID: SuSE-SA:2002:010
Date: Monday, Mar 11th 2002 20:45 MET
Affected products: 6.4, 7.0, 7.1, 7.2, 7.3
SuSE Linux Database Server
SuSE eMail Server III
SuSE Firewall
SuSE Linux Connectivity Server
SuSE Linux Enterprise Server 7
Vulnerability Type: remote command execution
Severity (1-10): 8
SuSE default package: yes
Other affected systems: systems with recent versions of the
compression library
Content of this advisory:
1) security vulnerability resolved: libz/zlib
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 zlib compression library is being used by many applications to
provide data compression/decompression routines. An error in a
decompression routine can corrupt the internal data structures of
malloc by a double call to the free() function. If the data processed
by the compression library is provided from an untrusted source, it
may be possible for an attacker to interfere with the process using the
zlib routines. The attack scenario includes a denial of service attack
and memory/data disclosure, but it may also be possible to insert
arbitrary code into the running program and to execute this code.
This update fixes the known problems in the libz/zlib as a permanent
fix. There exists no temporary workaround that can efficiently remedy
the problem.
It is expected that a large range of software is affected. The systems
affected are by no means limited to Linux systems or other open-source
based operating systems.
Note:
The libz compression library is being used by several hundred packages
in all SuSE products. While the update of the libz package as itself is
not problematic, it must be noted that many packages bring their own
compression library in their source code. If these packages link against
their own version of the libz compression library, their source needs
to be fixed as well. Considering the length of a combined Security
Announcement, SuSE Security publish a tandem-announcement, consisting
of two seperate Security Announcements released in quick succession:
SuSE-SA:2002:010 libz/zlib
SuSE-SA:2002:011 packages containing libz/zlib
Acknowledgements:
We thank Owen Taylor who tracked down the bug in the compression
library, and to Matthias Clasen for reporting the problem that seemed
to be located in the libpng at first.
We also thank Mark Adler and Jean-loup Gailly, the authors of the zlib
package, for their quick response in the double-free() matter.
SPECIAL INSTALL INSTRUCTIONS:
==============================
* Installation of the update package:
The installation of shared libraries on an actively running system
should be done with special care. During the update of the libz package,
runtime-linking the shared libraries is likely to fail for processes
that execute a new binary with the execve(2) system call. If at all
applicable, a system receiving the update should be kept as quiet as
possible during the time that the RPM command runs. In doubt, please
perform the update in Single User Mode ("init S"). The RPM command must
not be interrupted during its operation.
After performing the update, the processes that still use the old
version of the package must be restarted for the libz upgrade to
become effective. If you have performed the update in Single User Mode,
this has been done already, and you can safely return to your default
runlevel. If in doubt, reboot your system to make sure that the changes
are becoming effective.
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.
i386 Intel Platform:
SuSE-7.3
799491ca29f9bf95e3e38a73f25abea8
source rpm:
a4071506da6ab39dca5495530028d291
SuSE-7.2
2197aff65b09fb05b8969ace64d7a4a6
source rpm:
1694ed149ca946e7ea1cc2da3f14c181
SuSE-7.1
c309b104231c596bb81008c38a4e473c
source rpm:
950c86970cd7c3fc0a30cfab176769ac
SuSE-7.0
8bde6b53a78e5f920080bfa3b6a236a6
source rpm:
718c36c91cd0f97466cbb2303967d51c
SuSE-6.4
270fc89c1be6854288925a9326f9ca6e
source rpm:
625ed87653f820f7f65a4a8e045f6cc2
Sparc Platform:
SuSE-7.3
f890b6d04e9164fc2afa05241c0e94c9
source rpm:
818d39946dc6c73f425620fba546935c
SuSE-7.1
ff4ea0da2c5126311f654b2896a70dd9
source rpm:
c3a49ea61f2642d53e29c8a81e07bfd9
SuSE-7.0
b9e22f0ff9785ca1d226bd2c5e135909
source rpm:
25c2b7cd4e20da69b7d806551966bae8
AXP Alpha Platform:
SuSE-7.1
e8cd8561a1434c36afcccd856d79a483
source rpm:
f7c21774f76fb240205291c4e91ad83c
SuSE-7.0
15510fc7563e669145d28a69e0e77d8e
source rpm:
008bc8f743e64e26dccd89baf882b214
SuSE-6.4
7d29b7d929e4b36dd6268058bf3c7538
source rpm:
67a4bd496c7625aaa3049417930e97f8
PPC Power PC Platform:
SuSE-7.3
b06097a1496ca5fd7b3492c2ab4f7337
source rpm:
45127ca06e4b019b2e700a0c87c2edb6
SuSE-7.1
783a39b17295e169d344a5f7f1ad7e86
source rpm:
2ac1e404e8a6723b1eb101b7c7d118e8
SuSE-7.0
24901e0c7ccb6bf5bf17b2af60596d96
source rpm:
f9e6cda577a5007baa84fb9940ec718d
SuSE-6.4
b3580d5e1b3702c330957bde4422486c
source rpm:
32cbca2dbc911da128b5bd1d19789792
______________________________________________________________________________
2) Pending vulnerabilities in SuSE Distributions and Workarounds:
- Please see the following SuSE Security Announcement SuSE-SA:2002:011
(packages containing libz) for upgrade information regarding packages
that bring their own compression library in their source.
______________________________________________________________________________
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
md5sum
References
