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ESB-2010.0306 - [AIX] sendmail: Provide misleading information - Remote/unauthenticated

Date: 31 March 2010
References: ASB-2009.1073  ESB-2009.1450  

Click here for printable version
Click here for PGP verifiable version
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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2010.0306
                AIX sendmail SSL certificate vulnerability
                               31 March 2010

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           sendmail
Publisher:         IBM
Operating System:  AIX
Impact/Access:     Provide Misleading Information -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2009-4565 CVE-2009-2408 

Reference:         ASB-2009.1073
                   ESB-2009.1450

Original Bulletin: 
   http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd?mode=18&ID=5002&myns=paix53&mync=E

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IBM SECURITY ADVISORY

First Issued: Mon Mar 29 15:54:57 CDT 2010

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/sendmail_advisory.asc

                           VULNERABILITY SUMMARY

VULNERABILITY:   AIX sendmail SSL certificate vulnerability

PLATFORMS:       AIX 5.3, 6.1
                 VIOS 1.5, 2.1

SOLUTION:        Apply the fix or workaround as described below.

THREAT:          A man-in-the-middle attacker may be able to
                 spoof arbitrary SSL SMTP servers

CERT VU Number:  n/a
CVE Number:      CVE-2009-4565

Reboot required?    NO
Workarounds?        NO
Protected by FPM?   NO
Protected by SED?   NO

                           DETAILED INFORMATION

I. DESCRIPTION (from CVE)

    "sendmail before 8.14.4 does not properly handle a '\0' character
    in a Common Name (CN) field of an X.509 certificate, which (1)
    allows man-in-the-middle attackers to spoof arbitrary SSL-based
    SMTP servers via a crafted server certificate issued by a
    legitimate Certification Authority, and (2) allows remote
    attackers to bypass intended access restrictions via a crafted
    client certificate issued by a legitimate Certification Authority,
    a related issue to CVE-2009-2408."

II. PLATFORM VULNERABILITY ASSESSMENT

    Note: To use the following commands on VIOS you must first
    execute:

    oem_setup_env

    To determine if your system is vulnerable, execute the following
    command:

    lslpp -L bos.net.tcp.client

    The following fileset levels are vulnerable:

    AIX Fileset        Lower Level     Upper Level
    ------------------------------------------------
    bos.net.tcp.client 5.3.8.0         5.3.8.11
    bos.net.tcp.client 5.3.9.0         5.3.9.7
    bos.net.tcp.client 5.3.10.0        5.3.10.2
    bos.net.tcp.client 5.3.11.0        5.3.11.2
    bos.net.tcp.client 6.1.1.0         6.1.1.7
    bos.net.tcp.client 6.1.2.0         6.1.2.6
    bos.net.tcp.client 6.1.3.0         6.1.3.3
    bos.net.tcp.client 6.1.4.0         6.1.4.3

III. SOLUTION

    A. FIXES

        Fixes are now available.  The fixes are interim fixes.  The
        fixes can be downloaded from:

        http://aix.software.ibm.com/aix/efixes/security/sendmail_fix.tar

        The links above are to a tar file containing this signed
        advisory, fix packages, and PGP signatures for each package.

        AIX Level    VIOS Level       Fix
        ------------------------------------------------------
        5.3.8        1.5.2            IZ72834_08.100329.epkg.Z
        5.3.9                         IZ72835_09.100329.epkg.Z
        5.3.10                        IZ72836_10.100329.epkg.Z
        5.3.11                        IZ72837_11.100329.epkg.Z
        6.1.1                         IZ72528_01.100329.epkg.Z
        6.1.2        2.1.0            IZ72515_02.100329.epkg.Z
        6.1.3        2.1.1            IZ72510_03.100329.epkg.Z
        6.1.4        2.1.2            IZ70637_04.100329.epkg.Z

        To extract the fixes from the tar file:

        tar xvf sendmail_fix.tar
        cd sendmail_fix

        Verify you have retrieved the fixes intact:

        The checksums below were generated using the "csum -h SHA1"
        (sha1sum) commands and are as follows:

        csum -h SHA1 (sha1sum)                    filename
        ------------------------------------------------------------------
        5643989ef10e97eba58fb49c1399dc35fd4efe59  IZ70637_04.100329.epkg.Z
        9c3341316809bb06962840aa0f18157878784ec7  IZ72510_03.100329.epkg.Z
        261613c73338faeaffc69b5c6314b737ac6c52a1  IZ72515_02.100329.epkg.Z
        8b529961f722c4df077ba00a50d8daf293d64d71  IZ72528_01.100329.epkg.Z
        4a21abf1366ed3d0052c0fcf064ff01be546447a  IZ72834_08.100329.epkg.Z
        b30e05ec7a60e89ccbca0bad0b9092f38795ec98  IZ72835_09.100329.epkg.Z
        7821837e1954ebac5d83485348984033c93c8667  IZ72836_10.100329.epkg.Z
        3bfabc5510c3d55b9c599d8bae17b11e4967bf64  IZ72837_11.100329.epkg.Z

        To verify the sums, use the text of this advisory as input to
        csum or sha1sum. For example:

        csum -h SHA1 -i sendmail_advisory.asc
        sha1sum -c sendmail_advisory.asc

        These sums should match exactly. The PGP signatures in the tar
        file and on this advisory can also be used to verify the
        integrity of the fixes.  If the sums or signatures cannot be
        confirmed, contact IBM AIX Security and describe the
        discrepancy at the following addresses:

            security-alert@austin.ibm.com
            ahazlewo@us.ibm.com (Andy Hazlewood)

     B. FIX INSTALLATION

        IMPORTANT: If possible, it is recommended that a mksysb backup
        of the system be created.  Verify it is both bootable and
        readable before proceeding.

        Fix management documentation can be found at:

        http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html

        To preview fix installation:

        emgr -e fix_name -p         # where fix_name is the name of the  
                                    # fix being previewed.

        To install fix package:

        emgr -e fix_name -X         # where fix_name is the name of the  
                                    # fix being installed.

        IMPORTANT: The fix will not take affect until any running sendmail
        servers have been stopped and restarted with the following
        commands:
 
        stopsrc -s sendmail
        startsrc -s'sendmail' -a'-bd -q30m' 

    C. APARS

        IBM has assigned the following APARs to this problem:

        AIX Level           APAR number        Service pack date
        --------------------------------------------------------
        5.3.8               IZ72834            5/19/10 sp10
        5.3.9               IZ72835            5/19/10 sp7
        5.3.10              IZ72836            5/19/10 sp4
        5.3.11              IZ72837            5/19/10 sp4
        6.1.1               IZ72528            4/21/10 sp8
        6.1.2               IZ72515            4/21/10 sp7
        6.1.3               IZ72510            4/21/10 sp4
        6.1.4               IZ70637            4/21/10 sp4

        Subscribe to the APARs here:

        http://www.ibm.com/support/docview.wss?uid=isg1IZ72834
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72835
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72836
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72837
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72528
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72515
        http://www.ibm.com/support/docview.wss?uid=isg1IZ72510
        http://www.ibm.com/support/docview.wss?uid=isg1IZ70637

        By subscribing, you will receive periodic email alerting you
        to the status of the APAR, and a link to download the service
        pack when it becomes available.

IV. WORKAROUND

    None.

VI. CONTACT INFORMATION

    If you would like to receive AIX Security Advisories via email,
    please visit:
 
        http://www.ibm.com/systems/support
 
    and click on the "My notifications" link.
 
    To view previously issued advisories, please visit:
 
        http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd
 
    Comments regarding the content of this announcement can be
    directed to:

        security-alert@austin.ibm.com
        ahazlewo@us.ibm.com (Andy Hazlewood)
 
    To obtain the PGP public key that can be used to communicate
    securely with the AIX Security Team you can either:

        A. Send an email with "get key" in the subject line to:

            security-alert@austin.ibm.com

        B. Download the key from our web page:

  http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgpkey.txt

        C. Download the key from a PGP Public Key Server. The key ID is:

            0xF3807ECD
 
    Please contact your local IBM AIX support center for any
    assistance.
 
    eServer is a trademark of International Business Machines
    Corporation.  IBM, AIX and pSeries are registered trademarks of
    International Business Machines Corporation.  All other trademarks
    are property of their respective holders.

VII. ACKNOWLEDGMENTS

    This vulnerability was reported by sendmail.org for an issue found
    by Moxie Marlinspike.  This advisory was written by Andy Hazlewood
    (ahazlewo@us.ibm.com).

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===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
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