CERT Advisory CA-94:12.sendmail.vulnerabilities

CERT Advisory cert-advisory at cert.org
Thu Jul 14 20:39:27 UTC 1994

CA-94:12                         CERT Advisory
                                 July 14, 1994
                           Sendmail Vulnerabilities

This advisory supersedes all previous CERT advisories about sendmail(8) for
the vendors listed below.

There are two vulnerabilities in some vendors' versions of sendmail(8).
One, in the debug option, enables local users to gain root access.  The other,
in the error message header option, enables local users to read any file on
the system.  Both vulnerabilities are known in the intruder community.

The CERT Coordination Center is in contact with vendors concerning these
vulnerabilities.  Those who have patches available are listed at the end of
this advisory. If your vendor's name is not on the list, contact the vendor
directly for information on whether their version of sendmail(8) is vulnerable
and, if so, whether a patch is available.

The list of vendors and patches is reproduced in "CA-94:12.README" file.
As we receive additional information relating to this advisory, we will place it,
along with any clarifications, in the README file. CERT advisories and their
associated README files are available by anonymous FTP from info.cert.org. We
encourage you to check the README files regularly for updates on advisories
that relate to your site.


I.   Description

There is a problem with the debug option (-d) and/or the error message header
option (-oE) in some vendors' versions of sendmail(8).  An exploitation
script has been circulated for sendmail -d, and intruders are actively
exploiting this vulnerability.  As of the date of this advisory, we have not
received reports of the sendmail -oE vulnerability being exploited.

II.  Impact

     The sendmail -d vulnerability allows local users to gain root access.
     The sendmail -oE vulnerability allows local users to read any file on
     the system.

III. Solution

     Obtain and install the appropriate patch according to the
     instructions included with the patch.

     Below is a summary of the vendors listed in the current version of the
     CA-94:12.README file, and the status they have provided.  More complete
     information, including how to obtain patches, is provided in the
     appendix of this advisory and reproduced in the README file associated
     with this advisory. We will update the README file as we receive
     more information from vendors.

     Vendor or Source          Status
     ----------------          ------------
     Eric Allman               Versions 8.6.8 and 8.6.9 are available and not
     Amdahl                    Not vulnerable
     Apple                     Patch available
     Berkeley Software Design  Patch available
     Convex                    OS 11.0 not vulnerable; patch available for 10.x
     Data General              Patch available
     Digital Equipment         Patch available
     Hewlett Packard           Patch available
     IBM                       Patch available
     Open Software Foundation  Patch available
     Santa Cruz Operation      Patch in progress
     Sun                       Patch available

     Note:  Some sites may find it feasible to install Eric Allman's
     sendmail 8.6.9, which is in the public domain (see the appendix for
     details). However, depending upon the currently installed sendmail
     program, switching to a different sendmail may require significant
     effort.  The site administrator may need to become familiar with the
     new program, and the site's sendmail configuration file may require
     considerable modification in order to provide existing functionality.
     In some cases, the configuration file of the site's sendmail may be
     incompatible with that of sendmail 8.6.9.

The CERT Coordination Center wishes to thank all the vendors listed in this
advisory for their efforts in responding to this problem.

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

If you wish to send sensitive incident or vulnerability information to
CERT via electronic mail, CERT strongly advises that the e-mail be
encrypted.  CERT can support a shared DES key, PGP (public key
available via anonymous FTP on info.cert.org), or PEM (contact CERT
for details).

Internet E-mail: cert at cert.org
Telephone: 412-268-7090 (24-hour hotline)
           CERT personnel answer 8:30 a.m.-5:00 p.m. EST(GMT-5)/EDT(GMT-4),
           and are on call for emergencies during other hours.

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

Past advisories and their related README files, information about FIRST
representatives, and other information related to computer security are
available for anonymous FTP from info.cert.org.

Appendix: Vendor Information
Current as of July 14, 1994
See CA-94:12.README for updated information; this file supersedes

Below is information we have received from vendors who have patches available
or upcoming for the vulnerabilities described in this advisory, as well as
vendors who have confirmed that their products are not vulnerable. If your
vendor's name is not in one of these lists, contact the vendor directly for
information on whether their version of sendmail is vulnerable and, if so, the
status of patches to address the vulnerabilities.

Eric Allman

Sendmail versions 8.6.8 and 8.6.9 are not vulnerable.  The problem with -d was
fixed in sendmail 8.6.7, and -oE was fixed in sendmail 8.6.8. Even if you are
running 8.6.8, you may want to upgrade to 8.6.9 for the additional features.

Version 8.6.9 is available by anonymous FTP from ftp.cs.berkeley.edu in the
directory ucb/sendmail.

        MD5 (sendmail.8.6.9.base.tar.Z) = 9bffb19116e7fdbb6ec56ccf9344895b
        MD5 (sendmail.8.6.9.cf.tar.Z) = 37ecb776ec61f596d01fbb46bae6e72f
        MD5 (sendmail.8.6.9.misc.tar.Z) = e083dbd609bdaf4b46c52f2546b3d1e5
        MD5 (sendmail.8.6.9.xdoc.tar.Z) = 0df46586fbe767bf7060068331de7186


All versions of UTS 2.1 use smail rather than sendmail and are not vulnerable
to these problems.

Apple Computer, Inc.

A patch to version 3.1 of A/UX for these vulnerabilities is available by
anonymous FTP from ftp.support.apple.com or aux.support.apple.com; in each
case, a compressed, replacement version ( of sendmail is in

Filename        sendmail.Z
BSD checksum    02992  182
SysV checksum   10129  364
MD5 checksum    df4ca82f624ee8f4404c5e979e7e3d24

Uncompress this file using compress(1) and replace the previous version
(8.6.4) in /usr/lib; be sure to kill the running sendmail and restart.

Earlier versions of A/UX are not supported by this patch.  Users of previous
versions are encouraged by Apple to update their system to A/UX 3.1 or compile
and install the version of sendmail available from ftp.cs.berkeley.edu.

Customers should contact their reseller for any additional information.

Berkeley Software Design (BSDI)

Patches to sendmail for these problems in BSD/386 V1.1 are available from BSDI
customer support:

                BSDI Customer Support
                Berkeley Software Design, Inc.
                7759 Delmonico Drive
                Colorado Springs, CO 80919
                Toll Free: +1 800 ITS BSD8 (+1 800 486 2738)
                Phone: +1 719 260 8114
                Fax: +1 719 598 4238
                Email: support at bsdi.com


ConvexOS 11.0 (the most recent production OS) does not contain the

Convex customers running ConvexOS 10.x should install the CONVEX TAC PATCH
10.3.129, which is the full ConvexOS 11.0 mail system back ported to ConvexOS

The 10.3.129 README file is reproduced below:
The following patch information is provided by a member of the
CONVEX TAC. There is no express or implied warranty. The maintenance
of this patch is the responsibility of the installer. The existence of
this patch does not guarantee that the patch or its functionality
will be available in the next release of the product.

PATCH MODULE NAME: /usr/lib/sendmail

 Pre-installation precautions:

 if from tape:
        %installsw -i

        NOTE: If installing from tape, you must use a no-rewind tape
        device, such as /dev/rmt20 or /dev/rdat0n, /dev/eb0nr, or

 if from script:
        % ./Script.sh

The Convex Technical Assistance Center is available for additional
information at 800-952-0379.

Data General Corporation

DG/UX systems are not at risk from the -oE problem.

Patches will be made available for all supported releases of DG/UX for the -d
problem and it will be fixed in future releases of DG/UX starting with DG/UX
5.4 Release 3.10.  Affected sites should call their Customer Support Center
for information regarding this patch.

Digital Equipment Corporation

[The following information was excerpted from DEC SECURITY ADVISORY #0505.
Please contact DEC for a complete copy of that advisory.]

Products Affected:
        ULTRIX        Versions 4.3, 4.3A, V4.4
        DECnet-ULTRIX Version 4.2
        DEC OSF/1     Versions 1.2, 1.3, 1.3A, 2.0

SOLUTION: ULTRIX: Upgrade/Install ULTRIX to an minimum of V4.4 and install the
          Security Enhanced Kit

          DEC OSF/1: Upgrade/Install to a minimum of V1.2 and install
          the Security Enhanced Kit

          Please refer to the applicable Release Note information prior to
          upgrading your installation.

These kits are available from Digital Equipment Corporation by contacting
your normal Digital support channel or by request via DSNlink for electronic


CSCPAT_4060  V1.0   ULTRIX    V4.3 thru V4.4  (Includes DECnet-ULTRIX V4.2)
CSCPAT_4061  V1.0   DEC OSF/1 V1.2 thru V2.0
         These kits will not install on versions previous to ULTRIX V4.3
         or DEC OSF/1 V1.2.

Digital urges you to periodically review your system management and
security procedures.  Digital will continue to review and enhance the
security features of its products and work with customers to maintain
and improve the security and integrity of their systems.

    NOTE: For non-contract/non-warranty customers contact your local Digital
          support channels for information regarding these kits.


HP/UX does not support the -oE option.

To fix the -d problem, obtain patch PHNE_4533 from Hewlett-Packard.  This patch
may be obtained from HP via FTP (this is NOT anonymous FTP) or the HP
SupportLine.  To obtain HP security patches, you must first register with the
HP SupportLine.  The registration instructions are available by anonymous FTP
from info.cert.org in the file "pub/vendors/hp/supportline_and_patch_retrieval".


A patch for the -d vulnerability can be ordered from IBM as APAR IX44020
(PTF U431041).  AIX is not vulnerable to the -oE problem.  To order APARs
from IBM in the U.S., call 1-800-237-5511 and ask that it be shipped to
you as soon as it is available.  To obtain APARs outside of the U.S.,
contact your local IBM representative.

Open Software Foundation (OSF)

For OSF/1 R1.3:
     CR11057 describes how to fix the -d option problem in the sources.
     OSF/1 is not vulnerable to the -oE problem.

The Santa Cruz Operation, Inc. (SCO)

SCO systems are not affected by the -oE problem and a patch for the -d problem
on the following platforms will soon be available:

                SCO TCP/IP Release 1.2.0 for SCO XENIX
                SCO TCP/IP Release 1.2.1 for SCO UNIX
                SCO Open Desktop Release 3.0
                SCO Open Desktop Lite Release 3.0
                SCO Open Server Network System, Release 3.0
                SCO Open Server Enterprise System, Release 3.0

For more information contact SCO at:

        Electronic mail: support at sco.COM

        The Americas, Pacific Rim, Asia, and Latin America:
        6am-5pm Pacific Daylight Time (PDT)
        1-408-425-4726  (voice)
        1-408-427-5443  (fax)

        Europe, Middle East, Africa: 9am-5:30pm British Daylight Time (BST)

        +44 (0)923 816344 (voice)
        +44 (0)923 817781 (fax)

Sun Microsystems, Inc.

A. Patch list

    Sun has produced patches against these vulnerabilities for the versions
    of SunOS shown below.

        4.1.1           100377-15
        4.1.2           100377-15
        4.1.3           100377-15
        4.1.3_U1        101665-02
        5.1_x86         101352-03       (Solaris x86)
        5.1             100834-11       (Solaris 2.1)
        5.2             100999-59       (Solaris 2.2)
        5.3             101318-41       (Solaris 2.3)

B. Patch notes

    1. The last security-related patch for 4.1.x sendmail was
    distributed as 100377-08 (announced 23 December 1993). Revisions
    -09 through -14 were not related to security.

    2. The 4.1.1 patch includes a version built for the sun3 architecture.

    3. The 4.1.3 version of the patch is also applicable to 4.1.3C systems.

    4. The patch listed for 4.1.3_U1 (Solaris 1.1.1) applies to both
    the A and B versions. This is currently true for all U1 patches.

    5. One of the listed patches (100834-11, for SunOS 5.1) is actually a
    jumbo  kernel patch into which sendmail was bundled. The other two SunOS
    5.x patches, and all of the 4.1.x patches, contain only sendmail fixes.
    (Sun bundled all 5.x sendmails into jumbo kernel patches earlier this
    year, but later unbundled the 5.3 and 5.2 patches in response to customer
    complaints. The 5.1 sendmail will be unbundled as well later this summer.

    6. Sun releases new patch versions frequently. For this reason, when
    requesting patches you should ask for the specified "or later" version,
    e.g., "version 11 or later of patch 100834".

    Patches can be obtained from local Sun Answer Centers and Sunsolve.
    U.S. users can contact Sun a 800-USA-4SUN.  Sun can also be reached by
    e-mail at security-alert at sun.com.


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