Vulnerabilities in LibXML2 affect AIX,Vulnerabilities in LibXML2 affect VIOS

IBM SECURITY ADVISORY

First Issued: Mon Feb 22 08:06:13 CST 2016
|Updated: Thu Aug 11 12:11:35 CDT 2016
|Update: Changed the iFix name for the AIX 7.1.3 fix. No changes relevant
| to AIX 7.1.3 were made to the fix.

The most recent version of this document is available here:

http://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc
https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc
ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc

Security Bulletin: Vulnerabilities in LibXML2 affect AIX
CVE-2015-7941 CVE-2015-7942 CVE-2015-8241

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

SUMMARY:

There are multiple vulnerabilities in LibXML2 that impact AIX.

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

VULNERABILITY DETAILS:

CVEID: CVE-2015-7941 
DESCRIPTION: Libxml2 is vulnerable to a denial of service, caused by a
    heap-based buffer overflow in the xmlParseEntityDecl or
    xmlParseConditionalSections function. By using a specially-crafted XML
    data, a remote attacker could exploit this vulnerability to trigger an
    out-of-bounds read and cause the system to crash.
CVSS Base Score: 4.3 
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/108071 for more
    information.
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L)

CVEID: CVE-2015-7942
DESCRIPTION: Libxml2 is vulnerable to a denial of service, caused by a
    heap-based buffer overflow in the xmlParseConditionalSections function.
    By using a specially-crafted XML data, a remote attacker could exploit
    this vulnerability to trigger an out-of-bounds read and cause the
    system to crash.
CVSS Base Score: 4.3
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/108073 for more
    information.
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L)

CVEID: CVE-2015-8241
DESCRIPTION: libxml2 is vulnerable to a buffer overflow, caused by
    improper bounds checking by the XML parser in xmlNextChar. By using a
    malformed XML file, a local attacker could overflow a buffer and
    execute arbitrary code on the system or cause the application to crash.
CVSS Base Score: 5.9
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/108169 for more
    information.
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L)


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 = aix

    Fileset             Lower Level  Upper Level KEY 
    -----------------------------------------------------
    bos.rte.control     5.3.12.0     5.3.12.9    key_w_fs
    bos.rte.control     6.1.9.0      6.1.9.100   key_w_fs
    bos.rte.control     7.1.3.0      7.1.3.46    key_w_fs
    bos.rte.control     7.1.4.0      7.1.4.0     key_w_fs
    bos.rte.control     7.2.0.0      7.2.0.0     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 bos.rte.control

REMEDIATION:

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

        AIX Level APAR     Availability  SP   KEY
        ------------------------------------------------
        5.3.12    IV80617  N/A           N/A  key_w_apar
        6.1.9     IV80588  5/20/16       SP7  key_w_apar
        7.1.4     IV80586  5/20/16       SP2  key_w_apar
        7.2.0     IV80616  5/20/16       SP2  key_w_apar

        Subscribe to the APARs here:

        http://www.ibm.com/support/docview.wss?uid=isg1IV80617
        http://www.ibm.com/support/docview.wss?uid=isg1IV80588
        http://www.ibm.com/support/docview.wss?uid=isg1IV80586
        http://www.ibm.com/support/docview.wss?uid=isg1IV80616

        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/libxml2_fix2.tar
        http://aix.software.ibm.com/aix/efixes/security/libxml2_fix2.tar
        https://aix.software.ibm.com/aix/efixes/security/libxml2_fix2.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.x   IV80617s9a.160120.epkg.Z  key_w_fix
        6.1.9.x    IV80588s6a.160121.epkg.Z  key_w_fix

| 7.1.3.x IV80586s1a.160713.epkg.Z key_w_fix
7.1.4.x IV80586s1a.160713.epkg.Z key_w_fix
7.2.0.x IV80616s1a.160722.epkg.Z key_w_fix

        VIOS Level  Interim Fix (*.Z)         KEY
        -----------------------------------------------
        2.2.4.0     IV80588s6a.160121.epkg.Z  key_w_fix
        

        To extract the fixes from the tar file:

        tar xvf libxml2_fix2.tar
        cd libxml2_fix2

        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
        -----------------------------------------------------------------------------------------------------
        72045867e0660eb92ef58660f4594746d7d50643fefe72c8f8e53b77f80cdd18  IV80586s1a.160713.epkg.Z key_w_csum
        10ebb3487e540b54cd0620cfcd23c7d8ca68b789ad8bf98c93686da239ccedee  IV80588s6a.160121.epkg.Z key_w_csum
        9a013e6a7f82459eafd6380c0f4b1bd2fc974178944ee277e6e3eeaf4c235072  IV80616s1a.160722.epkg.Z key_w_csum
        8cff222b94a53ee6f2ddace7c6257280734c0396be5757309759d4ae2003be90  IV80617s9a.160120.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/libxml2_advisory2.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory2.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.

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

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 Feb 22 08:06:13 CST 2016
Updated: Fri May 27 08:25:24 CDT 2016
Update: Fix added for AIX 7.1.3.6.
Updated: Tue Jul  5 11:30:23 CDT 2016
Update: Changed impacted upper level fileset for AIX 7.1.4
   from: bos.rte.control 7.1.4.1
   to:   bos.rte.control 7.1.4.0
   The new upper fileset level appropriately reflects that AIX 7.1 TL4 SP2
   is not vulnerable.
Updated: Fri Jul 22 13:11:47 CDT 2016
Update: Changed impacted upper level fileset for AIX 7.2.0
   from: bos.rte.control 7.2.0.1
   to:   bos.rte.control 7.2.0.0
   The new upper fileset level appropriately reflects that AIX 7.2 TL0 SP2
   is not vulnerable. New iFixes issued for AIX 7.1 TL4 and 7.2 TL0 with
   corrected upper level fileset checks.  
Updated: Thu Jul 28 09:02:05 CDT 2016
Update: Clarified that many of the iFixes work across TLs, indepedent of
   SP.

| Updated: Thu Aug 11 12:11:35 CDT 2016
| Update: Changed the iFix name for the AIX 7.1.3 fix. No changes relevant
| to AIX 7.1.3 were made to the fix.

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

*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.