Vulnerability in OpenSSL affects AIX

IBM SECURITY ADVISORY

First Issued: Mon Apr 18 10:40:50 CDT 2016
|Updated: Tue Apr 19 09:58:35 CDT 2016
|Update: Clarified that the fixes for openssl_advisory18 cover the issue
| described in this bulletin.

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc

Security Bulletin: Vulnerability in OpenSSL affects AIX (CVE-2016-2842)

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

SUMMARY:

This bulletin addresses CVE-2016-2842 for AIX.

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

VULNERABILITY DETAILS:

OpenSSL vulnerabilities were disclosed on March 1, 2016 by the OpenSSL
Project. OpenSSL is used by AIX. AIX addressed the applicable CVEs with
the details provided in:

    Multiple vulnerabilities in OpenSSL affect AIX
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory18.asc

An additional CVE, CVE-2016-2842, was also fixed but was not initially
included in the March 1, 2016 OpenSSL Project announcement or in the
associated security bulletin for this product. This bulletin only
addresses CVE-2016-2842. Please see the bulletin linked above for the
other CVEs that were addressed by the March 1, 2016 OpenSSL Project.

CVEID: CVE-2016-2842
DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by the
    failure to verify that a certain memory allocation succeeds by the
    doapr_outch function. A remote attacker could exploit this
    vulnerability using a specially crafted string to cause an
    out-of-bounds write or consume an overly large amount of resources.
CVSS Base Score: 7.5
CVSS Temporal Score: See 
    https://exchange.xforce.ibmcloud.com/vulnerabilities/111304 for the 
    current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 5.3, 6.1, 7.1, 7.2
    VIOS 2.2.x

    The following fileset levels are vulnerable:
    
    key_fileset = osrcaix

    Fileset          Lower Level  Upper Level KEY 
    --------------------------------------------------
    openssl.base     0.9.8.401    0.9.8.2506  key_w_fs
    openssl.base     1.0.1.500    1.0.1.515   key_w_fs
    openssl.base     1.0.2.500    1.0.2.500   key_w_fs
    openssl.base    12.9.8.1100  12.9.8.2506  key_w_fs


    Note:  to find out whether the affected filesets are installed 
    on your systems, refer to the lslpp command found in AIX user's guide.

    Example:  lslpp -L | grep -i openssl.base

REMEDIATION:

    A. FIXES

        Fixes are available.

| Please note that these fixes are the same as provided in
| openssl_advisory18. The fixes for openssl_advisory18 also cover
| the CVE described in this bulletin, CVE-2016-2842.

        The fixes can be downloaded via ftp or http from:

        ftp://aix.software.ibm.com/aix/efixes/security/openssl_fix18.tar
        http://aix.software.ibm.com/aix/efixes/security/openssl_fix18.tar
        https://aix.software.ibm.com/aix/efixes/security/openssl_fix18.tar 

        The link above is to a tar file containing this signed
        advisory, fix packages, and OpenSSL signatures for each package.
        The fixes below include prerequisite checking. This will
        enforce the correct mapping between the fixes and AIX
        Technology Levels.
        
        Note that the tar file contains Interim fixes that are based on 
        OpenSSL version, and AIX OpenSSL fixes are cumulative.

        AIX Level           Interim Fix (*.Z)        Fileset Name(prereq for installation) KEY
        --------------------------------------------------------------------------------------------
        5.3, 6.1, 7.1, 7.2  IV83169m9b.160401.epkg.Z openssl.base(0.9.8.2506)              key_w_fix
        5.3, 6.1, 7.1, 7.2  IV83169m9a.160401.epkg.Z openssl.base(1.0.1.515)               key_w_fix
        5.3, 6.1, 7.1, 7.2  IV83169s9d.160401.epkg.Z openssl.base(1.0.2.500)               key_w_fix
        5.3, 6.1, 7.1, 7.2  IV83169m9c.160401.epkg.Z openssl.base(12.9.8.2506)             key_w_fix

        VIOS Level     Interim Fix (*.Z)             Fileset Name(prereq for installation) KEY
        --------------------------------------------------------------------------------------------
        2.2.*          IV83169m9b.160401.epkg.Z      openssl.base(0.9.8.2506)              key_w_fix
        2.2.*          IV83169m9a.160401.epkg.Z      openssl.base(1.0.1.515)               key_w_fix
        2.2.*          IV83169s9d.160401.epkg.Z      openssl.base(1.0.2.500)               key_w_fix
        2.2.*          IV83169m9c.160401.epkg.Z      openssl.base(12.9.8.2506)             key_w_fix
        
        IBM recommends that the same certificate should ONLY be shared with 
        identical server configuration and software. If the same 
        certificate were shared with different server(s) configuration or
        software, IBM recommends replacing the different server(s) with 
        unique certificates to protect against the DROWN exposure.

        
        To extract the fixes from the tar file:

        tar xvf openssl_fix18.tar
        cd openssl_fix18

        Verify you have retrieved the fixes intact:

        The checksums below were generated using the
        "openssl dgst -sha256 file" command as the followng:

        openssl dgst -sha256                                              filename                  KEY
        ------------------------------------------------------------------------------------------------------
        a5c629e778b9917e4d29edd996021a62874dcdc978d30cd56fb65395739d7f5a  IV83169m9b.160401.epkg.Z  key_w_csum
        21dd42076309599682c56a92e1fceca793b6d7bb26bffd4b30d9aea9a429e26a  IV83169m9a.160401.epkg.Z  key_w_csum
        7613b557bec19e1472a6e321ddff20d0026fee4c81097a81346a48f119347d67  IV83169s9d.160401.epkg.Z  key_w_csum
        14c8c21387f19eea212a964448a2ef1a0ecd1c8fb53f013b1035262d8aa6f831  IV83169m9c.160401.epkg.Z  key_w_csum
        
        
        These sums should match exactly. The OpenSSL 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 at
        [email protected] and describe the discrepancy.
        
        openssl dgst -sha1 -verify <pubkey_file> -signature <advisory_file>.sig <advisory_file>

        openssl dgst -sha1 -verify <pubkey_file> -signature <ifix_file>.sig <ifix_file>

        Published advisory OpenSSL signature file location:

        http://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory19.asc.sig 

    B. FIX AND INTERIM 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.

        To preview a fix installation:

        installp -a -d fix_name -p all  # where fix_name is the name of the
                                    # fix package being previewed.
        To install a fix package:

        installp -a -d fix_name -X all  # where fix_name is the name of the
                                    # fix package being installed.

        Interim fixes have had limited functional and regression
        testing but not the full regression testing that takes place
        for Service Packs; however, IBM does fully support them.

        Interim fix management documentation can be found at:

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

        To preview an interim fix installation:

        emgr -e ipkg_name -p         # where ipkg_name is the name of the
                                     # interim fix package being previewed.

        To install an interim fix package:

        emgr -e ipkg_name -X         # where ipkg_name is the name of the
                                     # interim fix package being installed.


WORKAROUNDS AND MITIGATIONS:

    None.

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

CONTACT US:

Note: Keywords labeled as KEY in this document are used for parsing
purposes.

If you would like to receive AIX Security Advisories via email,
please visit "My Notifications":

    http://www.ibm.com/support/mynotifications

To view previously issued advisories, please visit:

    http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq

Comments regarding the content of this announcement can be
directed to:

    [email protected]

To obtain the OpenSSL public key that can be used to verify the
signed advisories and ifixes:

    Download the key from our web page:

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

To obtain the PGP public key that can be used to communicate
securely with the AIX Security Team via [email protected] you
can either:

    A. Download the key from our web page:

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

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

        0x28BFAA12

Please contact your local IBM AIX support center for any
assistance.

REFERENCES:

Complete CVSS v3 Guide:  http://www.first.org/cvss/user-guide
On-line Calculator v3: http://www.first.org/cvss/calculator/3.0

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Mon Apr 18 10:40:50 CDT 2016 

| Updated: Tue Apr 19 09:58:35 CDT 2016
| Update: Clarified that the fixes for openssl_advisory18 cover the issue
| described in this bulletin.

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

*The CVSS Environment Score is customer environment specific and will
ultimately impact the Overall CVSS Score. Customers can evaluate the impact
of this vulnerability in their environments by accessing the links in the
Reference section of this Security Bulletin.

Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the
Common Vulnerability Scoring System (CVSS) is an “industry open standard
designed to convey vulnerability severity and help to determine urgency and
priority of response.” IBM PROVIDES THE CVSS SCORES “AS IS” WITHOUT WARRANTY
OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT
OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.