Vulnerability in BIND affects AIX,Vulnerability in BIND affects VIOS

IBM SECURITY ADVISORY

First Issued: Tues Nov 3 09:00:00 CDT 2015

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc
https://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc
ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc

Security Bulletin: Vulnerability in bind affects AIX (CVE-2015-5722)

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

SUMMARY:

ISC BIND is vulnerable to a denial of service, caused by the exit of a 
validating resolver due to an assertion failure in buffer.c. By 
parsing a malformed DNSSEC key, a remote attacker could exploit this 
vulnerability to cause a denial of service. 

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

VULNERABILITY DETAILS:

CVEID: CVE-2015-5722
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by the 
    exit of a validating resolver due to an assertion failure in 
    buffer.c. By parsing a malformed DNSSEC key, a remote attacker could 
    exploit this vulnerability to cause a denial of service.
CVSS Base Score: 7.5 
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/106089 for the
    current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 5.3, 6.1, 7.1
    VIOS 2.2.x

    The following AIX fileset levels are vulnerable:

    AIX Fileset        Lower Level Upper Level KEY
    --------------------------------------------------------
    bos.net.tcp.client 5.3.12.0    5.3.12.10   key_w_fs
    bos.net.tcp.client 6.1.8.0     6.1.8.20    key_w_fs
    bos.net.tcp.client 6.1.9.0     6.1.9.45    key_w_fs
    bos.net.tcp.client 7.1.2.0     7.1.2.20    key_w_fs
    bos.net.tcp.client 7.1.3.0     7.1.3.45    key_w_fs

    AIX Fileset (VIOS)  Lower Level           Upper Level
    ------------------------------------------------------------
    bos.net.tcp.client  6.1.0.0(2.2.0.0)      6.1.8.20(2.2.2.70)
    bos.net.tcp.client  6.1.0.0(2.2.0.0)      6.1.9.45(2.2.3.50)

    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 bos.net.tcp.client

REMEDIATION:

    A. APARS
        
        IBM has assigned the following APARs to this problem:

        AIX Level APAR     Availability  SP   KEY
        ---------------------------------------------------
        5.3.12    IV78092  N/A                key_w_apar
        6.1.8     IV78096  N/A                key_w_apar
        6.1.9     IV78091  12/04/15      SP6  key_w_apar
        7.1.2     IV78094  N/A                key_w_apar
        7.1.3     IV78095  2/26/16       SP6  key_w_apar


        Subscribe to the APARs here:

        http://www.ibm.com/support/docview.wss?uid=isg1IV78091
        http://www.ibm.com/support/docview.wss?uid=isg1IV78095

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

    B. FIXES

        Fixes are available.
        
        The fixes can be downloaded via ftp or http from:

        ftp://aix.software.ibm.com/aix/efixes/security/bind_fix9.tar
        http://aix.software.ibm.com/aix/efixes/security/bind_fix9.tar
        https://aix.software.ibm.com/aix/efixes/security/bind_fix9.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.

        AIX Level  Interim Fix (*.Z)         KEY
        ------------------------------------------------
        5.3.12.9   IV78092m9a.151103.epkg.Z  key_w_fix
        6.1.8.7    IV78096m7a.151021.epkg.Z  key_w_fix
        6.1.9.5    IV78091m5a.151020.epkg.Z  key_w_fix
        7.1.2.7    IV78094m7a.151020.epkg.Z  key_w_fix
        7.1.3.5    IV78095m5a.151019.epkg.Z  key_w_fix

        VIOS Level  Interim Fix (*.Z)         KEY
        ------------------------------------------------
        2.2.2.70    IV78096m7a.151021.epkg.Z  key_w_fix
        2.2.3.50    IV78091m5a.151020.epkg.Z  key_w_fix


        To extract the fixes from the tar file:

        tar xvf bind_fix9.tar
        cd bind_fix9

        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
        -----------------------------------------------------------------------------------------------------
        404c44a81b43cb8cacab75e732bc7c8eca27a869a137c619294fb3b91cf9f99c  IV78092m9a.151103.epkg.Z key_w_csum
        c2d3210404653dd91298efe732cb9b87ab0db9c6470f8c1ca540482b01690013  IV78096m7a.151021.epkg.Z key_w_csum
        95cb6237a23f136ae81f647d01f54a72c63594f8d8dcd4ff323523f096e01047  IV78091m5a.151020.epkg.Z key_w_csum
        8b10bce53ed6e225e29c8aa3663463d8320fe798c7b02740ba3b457ad294bb56  IV78094m7a.151020.epkg.Z key_w_csum
        ccc6e8abe8bf25e42fb08e4754f1b3e89d60c40bc73be4cec8a24af034c84c83  IV78095m5a.151019.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/bind_advisory9.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory9.asc.sig 

    C. 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.

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

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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 Guide:  http://www.first.org/cvss/cvss-guide.html
On-line Calculator V2:
    http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2

ACKNOWLEDGEMENTS:

None 

CHANGE HISTORY:

First Issued: Tues Nov 3 09:00:00 CDT 2015

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

*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.