||Home : Advisories : Buffer Overflow in Some Implementations of IMAP Servers|
||Buffer Overflow in Some Implementations of IMAP Servers
||20th July 1998
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CERT Advisory CA-98.09.imapd
Original issue date: July 20, 1998
Last revised: March 08, 1999 Updated IMAP Server information for
A complete revision history is at the end of this file.
Buffer Overflow in Some Implementations of IMAP Servers
The CERT Coordination Center has received reports regarding a
vulnerability in some implementations of IMAP servers.
The CERT/CC recommends that anyone running a vulnerable version of
this software upgrade to the current vendor-recommended version. Until
you can do so, we suggest disabling the vulnerable IMAP server.
We will update this advisory as we receive additional information. We
encourage you to check our web site regularly for updates to this
advisory that may relate to your site.
The CERT Coordination Center has received reports regarding a buffer
overflow in some implementations of IMAP servers. The overflow is in
library code from the University of Washington IMAP server that
handles SASL server-level authentication. This vulnerability is
different from the one discussed in CERT Advisory CA-97.09.imap_pop.
Information about this vulnerability has been posted to various public
mailing lists and newsgroups.
All versions of the University of Washington IMAP server prior to the
final (frozen, non-beta) version of imap-4.1 that support SASL
server-level authentication are vulnerable. The vulnerability affects
all University of Washington IMAP4rev1 servers prior to v10.234. Also,
any v10.234 server that was distributed with Pine 4.0 or any
imap-4.1.BETA is vulnerable.
Additionally, the vulnerability is present in other IMAP servers that
use library code from the University of Washington IMAP server to
handle SASL server-level authentication.
IMAP servers that share no code with the University of Washington
server are not vulnerable.
Some operating systems ship with a vulnerable version of this software
installed and enabled by default. Please refer to the Vendor
Information section below for more information about your vendor.
Remote intruders can execute arbitrary commands under the privleges of
the process running the vulnerable IMAP server. If the vulnerable IMAP
server is running as root, remote intruders can gain root access.
Determine if your version of imapd is vulnerable
To determine if a system is vulnerable, first telnet to port 143
on that host. If it is running an IMAP server, the banner will
show the version. For example:
% telnet host.your.domain.com 143
Connected to host.
Escape character is '^]'.
* OK host.your.domain.com IMAP4rev1 v10.190 server ready
In the above example, the IMAP server is the University of
Washington IMAP4rev1 v10.190. Since all University of Washington
IMAP4rev1 servers prior to v10.234 are vulnerable, the server in
the above example is vulnerable.
Please consult the Vendor Information section below for
information about other vulnerable IMAP servers.
Install the most recent version of imapd
Obtain and install the most recent version, or patch for your IMAP
server. Appendix A contains input from vendors who have provided
information for this advisory.
If you are unable to upgrade to a version that is not vulnerable,
we urge you to disable the IMAP server until you are able to
address the problem.
Appendix A - Vendor Information
Below is a list of the vendors who have provided information for this
advisory. We will update this appendix as we receive additional
information. If you do not see your vendor's name, the CERT/CC did not
hear from that vendor. Please contact the vendor directly.
IMAP Server Vendors
This does not affect the Cyrus imapd. Cyrus imapd shares no code with
the University of Washington imapd.
We are not affected by the problem described in the advisory. We do not
ship any University of Washington based software at this time. We have
never shipped any of the IMAP 4.x software from the University of
No ISOCOR products are affected by this problem. The N-PLEX implementation
shares no code with the University of Washington imapd.
No Microsoft products are affected by this problem.
The University of Washington imapd is shipped with our product
"Mobilenet/IMAP" and so it is vulnerable.
Netscape Messaging Server 3.55 and before are susceptible to this
vulnerability. However, it should be noted that Netscape Messaging
Server (any version) does NOT run as root and therefore, the exposure
is much more limited than the University of Washington example.
Regardless, we have released a patch available at
addresses this vulnerability.
Please refer to Sun Microsystems, Inc. Security Bulletin, "IMAP",
Number: 00177, distributed October 2, 1998 for additional information
relating to this vulnerability.
Patches and Checksums are available to all Sun customers via World Wide
Sun security bulletins are available via World Wide Web at:
University of Washington
A security problem has been detected with the University of Washington
IMAP server that is included in the Pine 4.00 distribution. This will
be fixed in the forthcoming Pine 4.01 maintenance release. Until then,
if you are using the UW IMAP server, please update it with the
This vulnerability affects all IMAP4rev1 servers prior to
v10.234. v10.234 may or may not be vulnerable; if it came from Pine
4.00 or from any imap-4.1.BETA then it is vulnerable. IMAP2bis
servers are immune. This problem is also fixed in the imap-4.2
toolkit, which is tentatively expected to be released in
conjunction with Pine 4.01. Any IMAP4rev1 server whose version
starts with "v11" will be immune.
Operating System Vendors
Berkeley Software Design, Inc.
The version of IMAP shipped with BSD/OS 2.1 and 3.0/3.1 is the older
version which does not include the vulnerability.
The version of IMAP which will be included in the upcoming 4.0 release
has been updated to include the security fixes.
Caldera: releasing patched imap-4.1; will release imap-4.2 as soon as
it becomes available.
Compaq Computer Corporation
(c) Copyright 1994, 1995, 1996, 1997, 1998 Compaq Computer Corporation.
All rights reserved.
SOURCE: Compaq Computer Corporation
Software Security Response Team USA
This reported problem is not present for the as shipped,
Compaq's Digital ULTRIX or Compaq's Digital UNIX
Operating Systems Software.
- Compaq Computer Corporation
We are investigating. We will provide an update when our
investigation is complete.
FreeBSD does not ship default with imap. However, there is a version
of imapd from Washington University in the FreeBSD ports collections,
known as imap-uw.
If anyone is using the imap port, we suggest fetching the latest revision
of imap and manually install it, or wait until the FreeBSD port is updated
and reinstall imap-uw using the ports system.
You can check the ports status at:
Our operating system, UXP/V, does not support imapd. Therefore, it is
not vulnerable to the above vulnerability.
HP does not ship the University of Washington IMAP server.
The version of imapd shipped with AIX 4.2 and 4.3 is vulnerable. We
are currently working on the following fixes which will be available
AIX 3.2.x: imapd not shipped (not vulnerable)
AIX 4.1.x: imapd not shipped (not vulnerable)
AIX 4.2.x: IX80446
AIX 4.3.x: IX80447
APARs may be ordered using Electronic Fix Distribution (via FixDist)
or from the IBM Support Center. For more information on FixDist,
or send e-mail to firstname.lastname@example.org with a subject of "FixDist".
IBM and AIX are registered trademarks of International Business Machines
NetBSD does not ship the UW imapd daemon in its standard or development
operating system releases. Our optional package system also does not
include it at this time.
OpenBSD has never shipped an imap daemon.
Red Hat Linux
Serious security problems have been found in all versions of imap shipped
with Red Hat Linux. If "rpm -q imap" shows that imap is installed on
your system, please upgrade to these new imap releases immediately, or
remove imap by running "rpm -e imap". Note that Red Hat's imap package
also provides a POP server, so only remove it if you don't need to provide
Thanks to everyone who helped find these problems, Olaf Kirch in particular.
Red Hat 5.0 and 5.1
rpm -Uvh http://ftp.redhat.com/updates/5.0/i386/imap-4.1.final-1.i386.rpm
rpm -Uvh http://ftp.redhat.com/updates/5.0/alpha/imap-4.1.final-1.alpha.rpm
rpm -Uvh http://ftp.redhat.com/updates/5.0/sparc/imap-4.1.final-1.sparc.rpm
Red Hat 4.2
rpm -Uvh http://ftp.redhat.com/updates/4.2/i386/imap-4.1.final-0.i386.rpm
rpm -Uvh http://ftp.redhat.com/updates/4.2/alpha/imap-4.1.final-0.alpha.rpm
rpm -Uvh http://ftp.redhat.com/updates/4.2/sparc/imap-4.1.final-0.sparc.rpm
The Santa Cruz Operation, Inc.
The following SCO products are vulnerable:
- SCO UnixWare 7
SCO OpenServer 5.0, SCO CMW+ 3.0, SCO Open Desktop/Open Server 3.0, and
UnixWare 2.1 is not vulnerable as University of Washington imapd is not
included in these platforms.
Binary versions of University of Washington imapd will be available
shortly from the SCO ftp site:
http://ftp.sco.com/SSE/sse014.ltr - cover letter
http://ftp.sco.com/SSE/sse014.tar.Z - replacement binaries
This fix is a binary for the following SCO operating systems:
- SCO UnixWare 7
For the latest security bulletins and patches for SCO products,
please refer to http://www.sco.com/security/.
Silicon Graphics Inc.
Please refer to Silicon Graphics Inc. Security Advisory, "University
of Washington imapd daemon Vulnerability," Number: 19980802-01-I,
distributed August 6, 1998 for additional information relating to this
The primary SGI anonymous FTP site for security information and patches
is sgigate.sgi.com (188.8.131.52). Security information and patches
are located under the directories ~ftp/security and ~ftp/patches,
respectively. The Silicon Graphics Security Headquarters Web page is
accessible at the URL http://www.sgi.com/Support/security/security.html.
The CERT Coordination Center thanks Olaf Kirch of Caldera Linux for
discovering and reporting the vulnerability. Additionally, we would
like to thank Mark Crispin and Lori Stevens of the University of
Washington for providing technical details and support in the
development of the advisory.
This document is available from:
CERT/CC Contact Information
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
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Our public PGP key is available from http://www.cert.org/CERT_PGP.key.
If you prefer to use DES, please call the CERT hotline for more
Getting security information
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Mar. 08, 1999 Updated IMAP Server information for ISOCOR.
Nov. 16, 1998 Updated patch information for Sun Microsystems, Inc.
Sept. 4, 1998 Added vendor information for Silicon Graphics, Inc.
Aug. 14, 1998 Added vendor information for Microsoft Corporation.
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