Archive of CERT general posting, CERT Advisory CA-98.09 - imapd

21/07/98, CERT Advisory CA-98.09 - imapd
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Subject: CERT Advisory CA-98.09 - imapd
From: CERT Advisory <>
Date: Mon, 20 Jul 1998 14:31:26 -0400
Organization: CERT(sm) Coordination Center - +1 412-268-7090


CERT* Advisory CA-98.09
Original issue date: July 20, 1998

Topic: 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.

- -------------------------------------------------------------------------

I. Description

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

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.

II. Impact

Remote intruders can execute arbitrary commands under the privileges of the
process running the vulnerable IMAP server. If the vulnerable IMAP server is
running as root, remote intruders can gain root access.

III. Solution

  A. 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 143
          Connected to host.
          Escape character is '^]'.
          * OK 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

     Please consult the Vendor Information section below for information
     about other vulnerable IMAP servers.

  B. 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.

  C. Workaround

     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

- -------------------------------------------------------------------------

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.

Esys Corporation

   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

NEC Corporation

   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 which
   addresses this vulnerability.

Sun Microsystems

   Sun Microsystems is working on patches for Solstice Internet Mail Server
   product versions 2.0, 3.1 and 3.2.

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
   following distribution:

   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 Linux

   Caldera: releasing patched imap-4.1; will release imap-4.2 as soon as
            it becomes available.


   6df741b4217f03bf773b54509a7d283a  imap-4.1.BETA-5.i386.rpm
   d3526121c68b611524fc72746204d752  imap-4.1.BETA-5.src.rpm

Compaq Computer Corporation

   (c) Copyright 1994, 1995, 1996, 1997, 1998 Compaq Computer Corporation.
   All rights reserved.

   SOURCE: Compaq Computer Corporation
           Compaq Services
           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

Data General

   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.

Hewlett-Packard Company

   HP does not ship the University of Washington IMAP server.

IBM Corporation

   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

   To Order
     APARs may be ordered using Electronic Fix Distribution (via FixDist)
     or from the IBM Support Center. For more information on FixDist,
     reference URL:

     or send e-mail to 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
   POP services.

   Thanks to everyone who helped find these problems, Olaf Kirch in particular.

   Red Hat 5.0 and 5.1

   rpm -Uvh

   rpm -Uvh

   rpm -Uvh

   Red Hat 4.2

   rpm -Uvh

   rpm -Uvh

   rpm -Uvh

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: - cover letter - 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

- -------------------------------------------------------------------------
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.

- -------------------------------------------------------------------------

If you believe that your system has been compromised, contact the CERT
Coordination Center or your representative in the Forum of Incident Response
and Security Teams (see

CERT/CC Contact Information


Phone +1 412-268-7090 (24-hour hotline)

CERT personnel answer 8:30-5:00 p.m. EST(GMT-5) / EDT(GMT-4) and are on call
for emergencies during other hours.

Fax +1 412-268-6989

Postal address:

CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890

Using encryption

We strongly urge you to encrypt sensitive information sent by email. We can
support a shared DES key or PGP. Contact the CERT/CC for more information.

Location of CERT PGP key

Getting security information

CERT publications and other security information are available from

CERT advisories and bulletins are also posted on the USENET newsgroup
To be added to our mailing list for advisories and bulletins, send email to

In the subject line, type

SUBSCRIBE your-email-address

- -------------------------------------------------------------------------

Copyright 1998 Carnegie Mellon University. Conditions for use, disclaimers,
and sponsorship information can be found in and
If you do not have FTP or web access, send mail to with
"copyright" in the subject line.

*CERT is registered in the U.S. Patent and Trademark Office.

- -------------------------------------------------------------------------

The authoritative version of this file is at:

A text only version of this file is at:

Revision history

Version: 2.6.2


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