AIX is vulnerable to a denial of service due to libxml2

IBM SECURITY ADVISORY

First Issued: Mon Sep 12 15:07:01 CDT 2022
|Updated: Mon Dec 12 12:49:47 CST 2022
|Update: Added iFixes for AIX 7.2 TL5 SP5 and VIOS 3.1.4.10.

The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc
https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc
ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc

Security Bulletin: AIX is vulnerable to a denial of service due to libxml2
(CVE-2022-29824)

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

SUMMARY:

A vulnerability in libxml2 could allow a remote attacker to cause a
denial of service (CVE-2022-29824). AIX uses libxml2 as part of its XML
parsing functions.

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

VULNERABILITY DETAILS:

CVEID: CVE-2022-29824
    https://vulners.com/cve/CVE-2022-29824
    https://vulners.com/cve/CVE-2022-29824
DESCRIPTION: GNOME libxml2 is vulnerable to a denial of service, caused
    by an integer overflows in several buffer handling functions in buf.c
    (xmlBuf*) and tree.c (xmlBuffer*). By persuading a victim to open a
    specially-crafted XML file, a remote attacker could exploit this
    vulnerability to cause a denial of service condition.
CVSS Base Score: 5.5
CVSS Temporal Score: See 
    https://exchange.xforce.ibmcloud.com/vulnerabilities/225645
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)


AFFECTED PRODUCTS AND VERSIONS:

    AIX 7.2, 7.3
    VIOS 3.1

    The following fileset levels are vulnerable:
    
    key_fileset = aix

    Fileset                 Lower Level  Upper Level KEY 
    ---------------------------------------------------------
    bos.rte.control         7.2.4.0      7.2.4.5     key_w_fs

| bos.rte.control 7.2.5.0 7.2.5.4 key_w_fs
bos.rte.control 7.2.5.100 7.2.5.101 key_w_fs
| bos.rte.control 7.2.5.200 7.2.5.200 key_w_fs
bos.rte.control 7.3.0.0 7.3.0.1 key_w_fs

    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
        -----------------------------------------------------
        7.2.4     IJ42381  **            N/A       key_w_apar
        7.2.5     IJ42339  **            SP06      key_w_apar
        7.3.0     IJ42341  **            SP04      key_w_apar

        VIOS Level APAR    Availability  SP        KEY
        -----------------------------------------------------
        3.1.1      IJ42381 **            N/A       key_w_apar
        3.1.2      IJ42378 **            3.1.2.60  key_w_apar
        3.1.3      IJ42379 **            3.1.3.40  key_w_apar

| 3.1.4 IJ42339 ** 3.1.4.20 key_w_apar

        Subscribe to the APARs here:

        http://www.ibm.com/support/pages/apar/IJ42339
        http://www.ibm.com/support/pages/apar/IJ42341
        http://www.ibm.com/support/pages/apar/IJ42378
        http://www.ibm.com/support/pages/apar/IJ42379
        http://www.ibm.com/support/pages/apar/IJ42381

        https://www.ibm.com/support/pages/apar/IJ42339
        https://www.ibm.com/support/pages/apar/IJ42341
        https://www.ibm.com/support/pages/apar/IJ42378
        https://www.ibm.com/support/pages/apar/IJ42379
        https://www.ibm.com/support/pages/apar/IJ42381

        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.

        AIX and VIOS fixes are available.

        The AIX and VIOS fixes can be downloaded via ftp or http from:

        ftp://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.tar
        http://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.tar
        https://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.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
        ----------------------------------------------
        7.2.4.4    IJ42381s6a.220909.epkg.Z  key_w_fix
        7.2.4.5    IJ42381s6a.220909.epkg.Z  key_w_fix
        7.2.4.6    IJ42381s6a.220909.epkg.Z  key_w_fix
        7.2.5.2    IJ42339s2a.220909.epkg.Z  key_w_fix
        7.2.5.3    IJ42339s4a.220907.epkg.Z  key_w_fix
        7.2.5.4    IJ42339s4a.220907.epkg.Z  key_w_fix

| 7.2.5.5 IJ42339s5a.221212.epkg.Z key_w_fix
7.3.0.1 IJ42341s2a.220907.epkg.Z key_w_fix
7.3.0.2 IJ42341s2a.220907.epkg.Z key_w_fix

        Please note that the above table refers to AIX TL/SP level as
        opposed to fileset level, i.e., 7.2.5.2 is AIX 7200-05-02.

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

        VIOS Level  Interim Fix (*.Z)         KEY
        -----------------------------------------------
        3.1.1.40    IJ42381s6a.220909.epkg.Z  key_w_fix
        3.1.1.50    IJ42381s6a.220909.epkg.Z  key_w_fix
        3.1.1.60    IJ42381s6a.220909.epkg.Z  key_w_fix
        3.1.2.21    IJ42378s2a.220909.epkg.Z  key_w_fix

| 3.1.2.30 IJ42378s2a.221010.epkg.Z key_w_fix
| 3.1.2.40 IJ42378s2a.221010.epkg.Z key_w_fix
3.1.3.10 IJ42379s4a.220909.epkg.Z key_w_fix
3.1.3.14 IJ42379s4a.220909.epkg.Z key_w_fix
3.1.3.21 IJ42379s4a.220909.epkg.Z key_w_fix
| 3.1.4.10 IJ42339s5a.221212.epkg.Z key_w_fix

        To extract the fixes from the tar file:

        tar xvf libxml2_fix3.tar
        cd libxml2_fix3

        Verify you have retrieved the fixes intact:

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

        openssl dgst -sha256                                              filename                 KEY
        -----------------------------------------------------------------------------------------------------
        f6d71f263ee414469dde9e6c3325fbc56031d3098ee8831f330e90c9e6b4dd9a  IJ42339s2a.220909.epkg.Z key_w_csum
        062b34620bc669451695f0de09580aef6e16f36f6430654dee5c403d23bc2fcc  IJ42339s4a.220907.epkg.Z key_w_csum

| 6a76b4c66b2ff7022b6a00eb2348b4c930af7293692631367f08e4bc65a753df IJ42339s5a.221212.epkg.Z key_w_csum
562b5f19d4db9e4c8835fd92f2e65038c2d765f0ff5e3ef40bad2d9110403a26 IJ42341s2a.220907.epkg.Z key_w_csum
f5ec81e718eef7d02adfb85a70f626073f684b93d72173212ba5675fe1eff001 IJ42378s2a.220909.epkg.Z key_w_csum
| 6d32716245fee8bc45fb961754eb53aaabc8630eb1e999c1e67cee237cc058cd IJ42378s2a.221010.epkg.Z key_w_csum
e00696e638622f82a2264b994fff9415b55c323a271da4c4bb84626046aa031c IJ42379s4a.220909.epkg.Z key_w_csum
f03c422e62ea819fa2dfc56342a16da80d20df4444667c6fae97ae95c1c2f6dd IJ42381s6a.220909.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 Support at
        http://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:

        http://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc.sig 

    C. FIX AND INTERIM FIX INSTALLATION

        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

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
On-line Calculator v3:
    http://www.first.org/cvss/calculator/3.0

RELATED INFORMATION:

IBM Secure Engineering Web Portal
    http://www.ibm.com/security/secure-engineering/bulletins.html

IBM Product Security Incident Response Blog
    https://www.ibm.com/blogs/psirt/

Security Bulletin: AIX is vulnerable to a denial of service due to 
    libxml2 (CVE-2022-29824)
    https://www.ibm.com/support/pages/node/6619729

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Mon Sep 12 15:07:01 CDT 2022

| Updated: Mon Oct 10 14:29:18 CDT 2022
| Update: Corrected the affected upper fileset levels for VIOS 3.1.2.30 and
| 3.1.2.40. Added iFixes with the correct prereqs for VIOS 3.1.2.30 and
| 3.1.2.40.
| Updated: Mon Dec 12 12:49:47 CST 2022
| Update: Added iFixes for AIX 7.2 TL5 SP5 and VIOS 3.1.4.10.

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

*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.