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Home » Hacking News » SuSE Security Announcement: cyrus-imapd (SuSE-SA:2002:048)

SuSE Security Announcement: cyrus-imapd (SuSE-SA:2002:048)

by Nikola Strahija on December 21st, 2002 The cyrus imapd contains a buffer overflow which could be exploited by remote attackers prior to logging in. Attackers could generate oversized error messages and overflow buffers inside imapd.

Package: cyrus-imapd
Announcement-ID: SuSE-SA:2002:048
Date: Fri Dec 20 18:00:00 MET 2002
Affected products: 7.1, 7.2, 7.3, 8.0, 8.1,
SuSE eMail Server III, 3.1,
SuSE Linux Connectivity Server,
SuSE Linux Enterprise Server 7,
SuSE Linux Enterprise Server 8,
SuSE Linux Office Server,
SuSE Linux Openexchange Server 4
Vulnerability Type: remote command execution
Severity (1-10): 6
SuSE default package: no
Cross References: -

Content of this advisory:
1) security vulnerability resolved: Buffer overflows in cyrus-imapd.
problem description, discussion, solution and upgrade information
2) pending vulnerabilities, solutions, workarounds:
- traceroute
- imap-2000c
3) standard appendix (further information)


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

The cyrus imapd contains a buffer overflow which could be exploited
by remote attackers prior to logging in. Attackers could generate oversized
error messages and overflow buffers inside imapd.
Additionally to this fix, an overflow in the SASL library (as used by the
cyrus imapd) has been fixed. This bug only affects SuSE Linux 8.1, the
SuSE Linux Enterprise Server 8 and the SuSE Linux Openexchange Server.

Since there is no workaround possible except shutting down the IMAP server,
we strongly recommend an update.

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.

To be sure the update takes effect you have to restart the IMAP server
by executing the following commands as root:

/etc/rc.d/cyrus restart

and (if using saslauthd)

/etc/rc.d/saslauthd restart

i386 Intel Platform:

patch rpm(s):
source rpm(s):

patch rpm(s):
source rpm(s):

source rpm(s):

source rpm(s):

source rpm(s):

Sparc Platform:

source rpm(s):

AXP Alpha Platform:

source rpm(s):

PPC Power PC Platform:

source rpm(s):

source rpm(s):


2) Pending vulnerabilities in SuSE Distributions and Workarounds:

Stefan Esser from e-matters discovered security critical bugs in the
MySQL server and client libraries. New packages are currently being built
and will soon be available. We will inform you with a separate advisory
when all packages for all platforms are available.

- traceroute
The recent update for the traceroute package did not fix all overflows
properly. New packages have been prepared and should already be available
on our ftp servers. The newly found bugs are not critical since the last
update for traceroute drops the superuser privileges before the overflow
can be triggered. However since the attacker could gain access to a raw
socket upon successfull exploitation, an update is recommended.

iDEFENSE reported various bugs in the CUPS printing system. These bugs could
lead to a remote compromise of the system. New packages are already available
on our ftp servers. We will inform you with a separate advisory when all
packages for all platforms are available.

- imap-2000c
The IMAP implementation of the University of Washington contained a buffer
overflow. This overflow happens after the authentication phase, so only
remote attackers with a valid IMAP account can exploit this bug. They will
obtain a shell with their user privileges if exploited properly. ;-)
Only versions less or eqal to imap-2000c (as shipped up to SL 7.3) are
The author of this imapd does not offer patches for older versions but
rather suggests to use the newest version available at
Due to the habbit of the author and the little impact of this bug, we
do not provide patched pre-build packages.


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.

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.

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