SuSE Linux Advisory: wu-ftpd
Jul 31, 2003, 21:58 (0 Talkback[s])
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SuSE Security Announcement
||Thursday, July 31st 2003 18:00 MEST
SuSE Linux Enterprise Server 7
SuSE Linux Connectivity Server
SuSE Linux Office Server
||remote buffer overflow
|SuSE default package:
Content of this advisory:
- security vulnerability resolved: wuftpd problem description,
discussion, solution and upgrade information
- pending vulnerabilities, solutions, workarounds
- standard appendix (further information)
1) problem description, brief discussion, solution, upgrade
Janusz Niewiadomski and Wojciech Purczynski of iSEC Security
Research have found a single byte buffer overflow in the Washington
University ftp daemon (wuftpd), a widely used ftp server for
Linux-like systems. It is yet unclear if this bug is (remotely)
exploitable. Positive exploitability may result in a remote root
compromise of a system running the wuftpd ftp daemon.
- SuSE Linux products do not contain wuftpd any more starting
with SuSE Linux 8.0 and SuSE Linux Enterprise Server 8. The wuftpd
package has been substituted by a different server implementation
of the file transfer protocol server.
- The affected wuftpd packages in products as stated in the
header of this announcement actually ship two different wuftpd ftp
daemon versions: The older version 2.4.x that is installed as
/usr/sbin/wu.ftpd, the newer version 2.6 is installed as
/usr/sbin/wu.ftpd-2.6 . The 2.4.x version does not contain the
defective parts of the code and is therefore not vulnerable to the
- If you are using the wuftpd ftp daemon in version 2.4.x, you
might want to update the package anyway in order not to risk an
insecure configuration once you switch to the newer version.
There exists no workaround that can fix this vulnerability on a
temporary basis other than just using the 2.4.x version as
mentioned above. The proper fix for the weakness is to update the
package using the provided update packages.
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.
Intel i386 Platform:
PPC Power PC Platform:
2) Pending vulnerabilities in SuSE Distributions and
- gnats Several security bugs were reported in gnats. The version
of gnats that comes with SuSE Linux is not vulnerable to these
- kopete Kopete is the KDE instant messenger. A bug in kopete's
gpg plugin can be abused to execute commands remotely. A fix will
be available as soon as possible.
- wget When handling long URLs, a buffer underrun may occur in
the wget program. This underrun may be exploitable remotely. The
update packages are available now on our ftp servers.
- emacs Due to insecure temporary file handling in the semi and
wemi library of GNU Emacs it is possible for a local attacker to
overwrite arbitrary files of the user running emacs. The fix is
currently being worked on.
- ethereal Several remote exploitable bugs were found in the
network analyzing tool ethereal. The update packages are available
on our ftp servers.
- tomcat Wrong file permission and clear passwords in the tomcat
default installation allows local users to gain security relevant
data by reading the file /opt/jakarta/tomcat/conf/tomcat-users.xml.
Please enable password encryption and revoke the read permissions
for 'group' and 'others' by adding the following line to
/opt/jakarta/tomcat/conf/tomcat-users.xml wwwrun.root 0700
and run the following command as root:
"chkstat -set /etc/permissions.local"
- heartbeat A format string bug in heartbeat's debug code can be
exploited by a remote attacker if the debug level is high and the
heartbeat daemon in configuered in an unsecure manner. The update
packages are being tested right now.
- freeradius A buffer overflow in the CHAP implementation of
freeradius leads to a remotely exploitable security hole which can
be abused to execute arbitrary code on the RADIUS server. The
update packages are being tested right now.
- traceroute(-nanog) An integer overflow in traceroute-nanog can
be abused to gain access to the raw ip socket. We are working on
- kdelibs Due to the fact of verifying the IP address instead of
the Common Name (CN) field of the X.509 certificate the SSL
implementation of KDE 2.2 and earlier is vulnerable to a MiM
attack. Only SuSE Linux 7.3 is affected by this problem. Update
packages are available on our FTP servers.
- man The mandb program which is part of the man package contains
a buffer overflow which allows local attackers to execute arbitrary
code as man user. New packages are already availabale on our ftp
- several minor bug fixes There are alot more minor security
updates in the queue. YOU (Yast Online Update) will inform you when
they appear. Alternatively you may want to monitor the following
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 <name-of-the-file.rpm> 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 list
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
<file.rpm> to verify the signature of the package, where
<file.rpm> 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 "email@example.com"
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:
- general/linux/SuSE security discussion. All SuSE security
announcements are sent to this list. To subscribe, send an email
For general information or the frequently asked questions (faq)
send mail to:
SuSE's security contact is <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 <email@example.com>
||SuSE Package Signing Key <firstname.lastname@example.org>