Buffer Overflow in Some Implementations of IMAP Servers
Last revised: March 08, 1999
Updated IMAP Server information for ISOCOR.
A complete revision history is at the end of this file.
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.
II. ImpactRemote 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 vulnerableTo 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 Trying 188.8.131.52... Connected to host. Escape character is '^]'. * OK host.your.domain.com IMAP4rev1 v10.190 server ready
Please consult the Vendor Information section below for information about other vulnerable IMAP servers.
Install the most recent version of imapdObtain 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.
WorkaroundIf 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 Washington.
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 http://help.netscape.com/products/server/messaging which 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 Web at: http://sunsolve.sun.com/sunsolve/pubpatches/patches.html Sun security bulletins are available via World Wide Web at: http://sunsolve.sun.com/sunsolve/secbulletins
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: ftp://ftp.cac.washington.edu/mail/imap.tar.Z 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. URL: ftp://ftp.caldera.com/pub/OpenLinux/updates/1.2/010 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
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: http://www.freebsd.org/ports/mail.html
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 soon: 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: http://aix.software.ibm.com/aix.us/swfixes/ or send e-mail to email@example.com with a subject of "FixDist". IBM and AIX are registered trademarks of International Business Machines Corporation.
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 ------------------- i386: rpm -Uvh ftp://ftp.redhat.com/updates/5.0/i386/imap-4.1.final-1.i386.rpm alpha: rpm -Uvh ftp://ftp.redhat.com/updates/5.0/alpha/imap-4.1.final-1.alpha.rpm SPARC: rpm -Uvh ftp://ftp.redhat.com/updates/5.0/sparc/imap-4.1.final-1.sparc.rpm Red Hat 4.2 ----------- i386: rpm -Uvh ftp://ftp.redhat.com/updates/4.2/i386/imap-4.1.final-0.i386.rpm alpha: rpm -Uvh ftp://ftp.redhat.com/updates/4.2/alpha/imap-4.1.final-0.alpha.rpm SPARC: rpm -Uvh ftp://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: ftp://ftp.sco.com/SSE/sse014.ltr - cover letter ftp://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 vulnerability. The primary SGI anonymous FTP site for security information and patches is sgigate.sgi.com (184.108.40.206). 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.
Copyright 1998 Carnegie Mellon University.
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.