Vulnerability in OpenSSL affects AIX (CVE-2018-0739)

IBM SECURITY ADVISORY

First Issued: Mon Apr 30 11:00:38 CDT 2018

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/openssl_advisory26.asc
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory26.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory26.asc

Security Bulletin: Vulnerability in OpenSSL affects AIX (CVE-2018-0739)

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

SUMMARY:

There is a vulnerability in OpenSSL used by AIX.

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

VULNERABILITY DETAILS:

CVEID: CVE-2018-0739 
https://vulners.com/cve/CVE-2018-0739
https://vulners.com/cve/CVE-2018-0739
DESCRIPTION:  Constructed ASN.1 types with a recursive definition (such
    as can be found in PKCS7) could eventually exceed the stack given 
    malicious input with excessive recursion. This could result in a 
    Denial Of Service attack. 
CVSS Base Score: 5.3 
CVSS Temporal Score: See 
    https://exchange.xforce.ibmcloud.com/vulnerabilities/140847 
    for the current score 
CVSS Environmental Score*: Undefined
CVSS Vector:(CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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    1.0.2.500      1.0.2.1300     key_w_fs
    openssl.base    20.13.102.1000 20.13.102.1300 key_w_fs

    Note:  
    A. 0.9.8, 1.0.1 OpenSSL versions are out-of-support. Customers are 
       advised to upgrade to currently supported OpenSSL 1.0.2 version.

    B. Latest level of OpenSSL fileset is available from the web download site:
https://www14.software.ibm.com/webapp/iwm/web/reg/download.do?source=aixbp&lang=en_US&S_PKG=openssl&cp=UTF-8

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

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

REMEDIATION:

    FIXES

        The fixes can be downloaded via ftp or http from:

        ftp://aix.software.ibm.com/aix/efixes/security/openssl_fix26.tar
        http://aix.software.ibm.com/aix/efixes/security/openssl_fix26.tar
        https://aix.software.ibm.com/aix/efixes/security/openssl_fix26.tar 

        The links above are 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.

        You must be on the 'prereq for installation' level before
        applying the interim fix. This may require installing a new
        level(prereq version) first.


        AIX Level           Interim Fix (*.Z)        Fileset Name(prereq for installation) KEY
        --------------------------------------------------------------------------------------------
        5.3, 6.1, 7.1, 7.2  102ma_ifix.180410.epkg.Z   openssl.base(1.0.2.1300)             key_w_fix
        5.3, 6.1, 7.1, 7.2  fips_102ma.180410.epkg.Z   openssl.base(20.13.102.1300)         key_w_fix

        VIOS Level     Interim Fix (*.Z)             Fileset Name(prereq for installation) KEY
        --------------------------------------------------------------------------------------------
        2.2.*          102ma_ifix.180410.epkg.Z        openssl.base(1.0.2.1300)             key_w_fix
        2.2.*          fips_102ma.180410.epkg.Z        openssl.base(20.13.102.1300)         key_w_fix

        
        To extract the fixes from the tar file:

        tar xvf openssl_fix26.tar
        cd openssl_fix26

        Verify you have retrieved the fixes intact:

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

        openssl dgst -sha256                                              filename                  KEY
        ------------------------------------------------------------------------------------------------------
        bfd40e466a6c7976fcf0cb46474087c550c043dc98b0be57689975388100bfdf  102ma_ifix.180410.epkg.Z    key_w_csum
        ee752e4a70cd46295141d7441a99e019db0391f6539881c5d185433dd0cd42ae  fips_102ma.180410.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 Support at
        https://ibm.com/support/ 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_advisory26.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/openssl_advisory26.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory26.asc.sig 

    B. FIX AND INTERIM FIX INSTALLATION

        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.

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please visit "My Notifications":

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To view previously issued advisories, please visit:

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

Contact IBM Support for questions related to this announcement:

    http://ibm.com/support/
    https://ibm.com/support/

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

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

REFERENCES:

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

RELATED INFORMATION:

Security Bulletin: Vulnerability in OpenSSL affects AIX (CVE-2018-0739)
    http://www-01.ibm.com/support/docview.wss?uid=isg3T1027517       

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Mon Apr 30 11:00:38 CDT 2018

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

*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.