Vulnerability in OpenSSL affects AIX (CVE-2018-0732)

IBM SECURITY ADVISORY

First Issued: Wed Sep 19 08:44:29 CDT 2018

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/openssl_advisory28.asc
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory28.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory28.asc

Security Bulletin: Vulnerability in OpenSSL affects AIX (CVE-2018-0732)

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

SUMMARY:

There is a vulnerability in OpenSSL used by AIX.

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

VULNERABILITY DETAILS:

CVEID: CVE-2018-0732
https://vulners.com/cve/CVE-2018-0732
https://vulners.com/cve/CVE-2018-0732
DESCRIPTION: OpenSSL is vulnerable to a denial of service, caused by the
    sending of a very large prime value to the client by a malicious server
    during key agreement in a TLS handshake. By spending an unreasonably
    long period of time generating a key for this prime, a remote attacker
    could exploit this vulnerability to cause the client to hang.
CVSS Base Score: 5.3
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/144658
    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      1.0.2.1500     key_w_fs
    openssl.base    20.13.102.1000 20.13.102.1500 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_fix28.tar
        http://aix.software.ibm.com/aix/efixes/security/openssl_fix28.tar
        https://aix.software.ibm.com/aix/efixes/security/openssl_fix28.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  102oa_ifix.180906.epkg.Z   openssl.base(1.0.2.1500)            key_w_fix
        5.3, 6.1, 7.1, 7.2  fips_102oa.180910.epkg.Z   openssl.base(20.13.102.1500)        key_w_fix

        VIOS Level     Interim Fix (*.Z)             Fileset Name(prereq for installation) KEY
        --------------------------------------------------------------------------------------------
        2.2.x         102oa_ifix.180906.epkg.Z        openssl.base(1.0.2.1500)             key_w_fix 
        2.2.x         fips_102oa.180910.epkg.Z        openssl.base(20.13.102.1500)         key_w_fix


        To extract the fixes from the tar file:

        tar xvf openssl_fix28.tar
        cd openssl_fix28

        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
        -----------------------------------------------------------------------------------------------------
        d060188b871e792bc29752dd4ab4308e8b11e2a90d5dee1902a8b8683a4de9de  102oa_ifix.180906.epkg.Z key_w_csum
        6edf3bf56a2e4ec9d2e3e0f0a28c00c740f1be5cdb524d050af0b842908b89cd  fips_102oa.180910.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_advisory28.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/openssl_advisory28.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory28.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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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:

ftp://ftp.software.ibm.com/systems/power/AIX/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-2018-0732)
    https://www-01.ibm.com/support/docview.wss?uid=ibm10731039

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Wed Sep 19 08:44:29 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.