SuSE Linux Advisory: nfs-utils
Jul 15, 2003, 14:29 (0 Talkback[s])
SuSE Security Announcement
||Tue Jul 15 14:00:00 MEST 2003
||7.2, 7.3, 8.0, 8.1, 8.2 SuSE Linux Database Server, SuSE eMail
Server III, 3.1 SuSE Linux Enterprise Server 7, 8 SuSE Linux
Firewall on CD/Admin host SuSE Linux Connectivity Server SuSE Linux
Office Server SuSE Linux Desktop 1.0
||remote code execution
|SuSE default package:
Content of this advisory:
- security vulnerability resolved: Off by one bug in rpc.mountd.
problem description, discussion, solution and upgrade
- pending vulnerabilities, solutions, workarounds:
- standard appendix (further information)
1) problem description, brief discussion, solution, upgrade
The nfs-utils package contains various programs to offer and
manage certain RPC services such as the rpc.mountd. iSEC Security
Research has reported an off-by-one bug in the xlog() function used
by the rpc.mountd. It is possible for remote attackers to use this
off-by-one overflow to execute arbitrary code as root. Some of the
products listed above seem not vulnerable to this one byte overflow
due to the stack alignment generated by the compiler during the
build. Nevertheless, since there is no easy workaround except
shutting down the RPC services, an update is strongly recommended
for every product listed above.
This update needs to be applied to both NFS servers and clients,
as the vulnerable function is used by mountd and statd.
You can either restart these services manually, or use the
corresponding init scripts:
"rcnfsserver restart" (for the NFS server)
"rcnfs restart" (for the NFS client)
Depending on your setup, it may be less disruptive to restart
the two daemons manually.
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:
PPC Power PC Platform:
2) Pending vulnerabilities in SuSE Distributions and
- xpdf/acroread A problem regarding handling of external URLs by
various PDF readers has been reported by CERT. Attackers could
execute arbitrary commands as the user viewing the document by
embedding shell meta characters in URLs. The xpdf PDF viewer as
shipped with SuSE is not vulnerable to this attack due to its
configuration. For the acrobat PDF reader we will provide updates
on our ftp servers shortly.
- lbreakout Various format string bugs in the code of the game
lbreakout were reported for version 2-2.5. These bugs can be
exploited remotely. SuSE Linux does not ship this vulnerable
version of lbreakout.
- Eterm A buffer overflow in eterm while handling the environment
variable ETERMPATH can lead to local privilege escalation. SuSE do
not ship eterm with higher privileges.
- gnats Several security bugs were reported in gnats. These bugs
will be fixed and update packages will released soon.
- unzip Unzip can be tricked into overwriting files by using
special zip archives. Fixed packages are available on our ftp
3) standard appendix: authenticity verification, additional
- 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:
- md5sums as provided in the (cryptographically signed)
- using the internal gpg signatures of the rpm package.
- execute the command md5sum 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@example.com), 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.
- 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. Prerequisites:
- gpg is installed
- 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 "firstname.lastname@example.org"
upon installation or upgrade, provided that the package gpg is
installed. The file containing the public key is placed at the
top-level 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 subscribe:
For general information or the frequently asked questions (faq)
send mail to:
SuSE's security contact is <<A
HREF="mailto:email@example.com">firstname.lastname@example.org> 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.
||SuSE Security Team <<A
||SuSE Package Signing Key <<A