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
**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 Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

The following fileset levels are vulnerable:

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/Fixes

A. APARS

IBM has assigned the following APARs to this problem:

Subscribe to the APARs here:

<https://www.ibm.com/support/pages/apar/IJ42677&gt;

<https://www.ibm.com/support/pages/apar/IJ42939&gt;

<https://www.ibm.com/support/pages/apar/IJ43073&gt;

<https://www.ibm.com/support/pages/apar/IJ43218&gt;

<https://www.ibm.com/support/pages/apar/IJ43599&gt;

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&gt;

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.

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.

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:

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/&gt; 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&gt;

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&gt;

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