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Home » Hacking News » SuSE-SA:2002:037-heartbeat


by Nikola Strahija on October 15th, 2002 Content of this advisory: 1) security vulnerability resolved: format string bug in heartbeat problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds: - util-linux - dhcpcd - heimdal - logsurfer - ghostscript 3) standard appendix (further information)

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

Heartbeat is a monitoring service that is used to implement
failover in high-availablity environments. It can be configured to
monitor other systems via serial connections, or via UDP/IP.

Several format string bugs have been discovered in the heartbeat
package. One of these format string bugs is in the normal path
of execution, all the remaining ones can only be triggered if
heartbeat is running in debug mode. Since heartbeat is running with
root privilege, this problem can possibly be exploited by remote
attackers, provided they are able to send packets to the UDP port
heartbeat is listening on (port 694 by default).

Vulnerable versions of heartbeat are included in SuSE Linux 8.0 and
SuSE Linux 8.1.

As a workaround, make sure that your firewall blocks all traffic
to the heartbeat UDP port.

The proper fix is to upgrade to the packages provided by SuSE.
In addition to fixing the format string bug, this update also
changes heartbeat to perform processing of network packets as
user "nobody" instead of root. The update package for SuSE Linux
8.1 also fixes a boot time problem with heartbeat.

SuSE wishes to thank Nathan Wallwork for reporting the bug, and Alan
Robertson for his assistance in dealing with this problem. For more
information on this vulnerability, please refer to

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.

i386 Intel Platform:

- being rebuilt

source rpm:


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

- util/util-linux
The mount and umount program did not set their umask properly before
creating the mtab file. Local attackers could abuse the mount program
to put arbitrary content into the /etc/mtab file. New packages are
available on our ftp servers which fix this problem. An update is

- dhcpcd
The dhcpcd DHCP client daemon has the ability to execute an
external script named /sbin/dhcpcd-.exe when assigning
a new IP address. It is not installed by default, however.

The script obtains the DHCP information by sourcing a file named
/var/lib/dhcpcd/, containing a list
of shell variable assignments. Insufficient quoting of these
assignments allowed malicious DHCP servers (or attackers able
to spoof DHCP responses) to execute arbitrary shell commands on
the DHCP client if the user had installed the script.

- heimdal
Within the SuSE Advisory SuSE-SA:2002:034 regarding the Heimdal packages,
the following rpm was missing in the list:


If you updated the Heimdal packgages for SuSE 7.3-i386, make sure you also
update this package.

- logsurfer
New logsurfer (logsurf in SuSE-7.0) packages are available for
download. These packages fix two errors (off-by-one overflow,
uninitialized memory) in the logsurfer package that can lead to
a crash of the program, resulting in a denial of service. It is
unknown if the two bugs can be used to execute arbitrary code in
the context of the logsurfer program.

- ghostscript (CVE CAN-2002-0363)
In ghostscript 6.50, setting the interpreter to SAFE mode was
reversible. This could be exploited to subvert the accounts of
users viewing malicious PostScript[tm], as well as the lp acount
if the print system was enabled.
SuSE has released updated RPMs for SuSE Linux 7.3 and SuSE Linux
Enterprise Server 7 for PowerPC. No other SuSE platform is affected.

- gv/ggv/kghostview (CVE CAN-2002-0832)
The ghostview (gv) code had several buffer overflows when handling
PostScript[tm] structural comments. These were also present in the
GNOME and KDE PostScript viewers derived from it. SuSE has released
fixed packages for these vulnerabilities.


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 < announcement.txt | gpg --import
SuSE Linux distributions version 7.1 and thereafter install the
key "[email protected]" 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 .

- SuSE runs two security mailing lists to which any interested party may

[email protected]
- general/linux/SuSE security discussion.
All SuSE security announcements are sent to this list.
To subscribe, send an email to

[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.

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