AIX is vulnerable to a buffer overflow due to X11

IBM SECURITY ADVISORY

First Issued: Tue Jan 17 09:54:47 CST 2023

The most recent version of this document is available here:

https://aix.software.ibm.com/aix/efixes/security/x11_advisory.asc

Security Bulletin: AIX is vulnerable to a buffer overflow due to X11
(CVE-2022-47990)

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

SUMMARY:

A vulnerability in X11 on AIX could allow a non-privileged local user to
cause a buffer overflow that could result in a denial of service or
arbitrary code execution (CVE-2022-47990).

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

VULNERABILITY DETAILS:

CVEID: CVE-2022-47990
    https://vulners.com/cve/CVE-2022-47990
    https://vulners.com/cve/CVE-2022-47990
DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a
    vulnerability in X11 to cause a buffer overflow that could result in
    a denial of service or arbitrary code execution.
CVSS Base Score: 6.2
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/243556
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 7.1, 7.2, 7.3
    VIOS 3.1

    The following fileset levels are vulnerable:
    
    key_fileset = aix

    Fileset                 Lower Level  Upper Level KEY 
    ---------------------------------------------------------
    X11.base.lib            7.1.5.0      7.1.5.34    key_w_fs
    X11.base.lib            7.2.5.0      7.2.5.1     key_w_fs
    X11.base.lib            7.2.5.100    7.2.5.100   key_w_fs
    X11.base.lib            7.3.0.0      7.3.0.0     key_w_fs

    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 X11.base.lib

REMEDIATION:

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

        AIX Level APAR     Availability  SP        KEY
        -----------------------------------------------------
        7.1.5     IJ43073  **            SP11      key_w_apar
        7.2.5     IJ42677  **            SP05      key_w_apar
        7.3.0     IJ42939  **            SP03      key_w_apar

        VIOS Level APAR    Availability  SP        KEY
        -----------------------------------------------------
        3.1.2      IJ43599 **            3.1.2.50  key_w_apar
        3.1.3      IJ43218 **            3.1.3.30  key_w_apar

        Subscribe to the APARs here:

        https://www.ibm.com/support/pages/apar/IJ42677
        https://www.ibm.com/support/pages/apar/IJ42939
        https://www.ibm.com/support/pages/apar/IJ43073
        https://www.ibm.com/support/pages/apar/IJ43218
        https://www.ibm.com/support/pages/apar/IJ43599

        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

        IBM strongly recommends addressing the vulnerability now.

        The fixes can be downloaded via sftp or https from:

        https://aix.software.ibm.com/aix/efixes/security/x11_fix.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.
        
        AIX Level  Interim Fix (*.Z)         KEY
        ----------------------------------------------
        7.1.5.8    IJ43073sAa.221227.epkg.Z  key_w_fix
        7.1.5.9    IJ43073sAa.221227.epkg.Z  key_w_fix
        7.1.5.10   IJ43073sAa.221227.epkg.Z  key_w_fix
        7.2.5.3    IJ42677s4a.221227.epkg.Z  key_w_fix
        7.2.5.4    IJ42677s4a.221227.epkg.Z  key_w_fix
        7.3.0.1    IJ42939s2a.221227.epkg.Z  key_w_fix
        7.3.0.2    IJ42939s2a.221227.epkg.Z  key_w_fix

        Please note that the above table refers to AIX TL/SP level as
        opposed to fileset level, i.e., 7.2.5.4 is AIX 7200-05-04.

        Please reference the Affected Products and Version section above
        for help with checking installed fileset levels.

        VIOS Level  Interim Fix (*.Z)         KEY
        -----------------------------------------------
        3.1.2.21    IJ43599s2a.221227.epkg.Z  key_w_fix
        3.1.2.30    IJ43599s2a.221227.epkg.Z  key_w_fix
        3.1.2.40    IJ43599s2a.221227.epkg.Z  key_w_fix
        3.1.3.10    IJ43218s4a.221227.epkg.Z  key_w_fix
        3.1.3.14    IJ43218s4a.221227.epkg.Z  key_w_fix
        3.1.3.21    IJ43218s4a.221227.epkg.Z  key_w_fix

        To extract the fixes from the tar file:

        tar xvf x11_fix.tar
        cd x11_fix

        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
        -----------------------------------------------------------------------------------------------------
        14cbb2b9dd2ef656fecad2435cbaa25e671f4af95687157976f98353e53188c4  IJ42677s4a.221227.epkg.Z key_w_csum
        244a069d456404b1bccc17c200bbcc590b2de6b8b9fdfe9508f1ef719b28395a  IJ42939s2a.221227.epkg.Z key_w_csum
        4154bb1dcbcee62e94ffb5bb6ab797fed074c7c81f101bbbe93c59adadb073b3  IJ43073sAa.221227.epkg.Z key_w_csum
        47b0da532dde030e744ec65d2fb816475de656e4b1494f36a575fb76311a08b2  IJ43218s4a.221227.epkg.Z key_w_csum
        a978251ccc42081acf62b9adf4619fcb07d75e83d215dd8a4e5e4a78fe2136fc  IJ43599s2a.221227.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 -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

        openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]

        Published advisory OpenSSL signature file location:

        https://aix.software.ibm.com/aix/efixes/security/x11_advisory.asc.sig

    C. 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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To obtain the OpenSSL public key that can be used to verify the
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    Download the key from our web page:

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

REFERENCES:

Review this information as needed, no action required.

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

RELATED INFORMATION:

Security Bulletin: AIX is vulnerable to a buffer overflow due to X11
    (CVE-2022-47990)
    https://www.ibm.com/support/pages/node/6855827

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Tue Jan 17 09:54:47 CST 2023

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

*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.