Summary

There is a vulnerability in OpenSSL used by AIX.

Vulnerability Details

CVEID:CVE-2021-3712
**DESCRIPTION:**OpenSSL could allow a remote attacker to obtain sensitive information, caused by an out-of-bounds read when processing ASN.1 strings. By sending specially crafted data, an attacker could exploit this vulnerability to read contents of memory on the system or perform a denial of service attack.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/208073 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L)

Affected Products and Versions

The following fileset levels are vulnerable:

Note:

A. 0.9.8, 1.0.1 OpenSSL versions are out-of-support. Customers are advised to upgrade to currently supported OpenSSL 1.0.2 version.

B. Latest level of OpenSSL fileset is available from the web download site:

https://www-01.ibm.com/marketing/iwm/iwm/web/pickUrxNew.do?source=aixbp&S_PKG=openssl

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 openssl.base

Remediation/Fixes

A. FIXES

The fixes can be downloaded via ftp or http from:

ftp://aix.software.ibm.com/aix/efixes/security/openssl_fix34.tar

<http://aix.software.ibm.com/aix/efixes/security/openssl_fix34.tar&gt;

<https://aix.software.ibm.com/aix/efixes/security/openssl_fix34.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.

Note that the tar file contains Interim fixes that are based on OpenSSL version, and AIX OpenSSL fixes are cumulative.

You must be on the ‘prereq for installation’ level before applying the interim fix. This may require installing a new level(prereq version) first.

To extract the fixes from the tar file:

tar xvf openssl_fix34.tar

cd openssl_fix34

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:

<http://aix.software.ibm.com/aix/efixes/security/openssl_advisory34.asc.sig&gt;

<https://aix.software.ibm.com/aix/efixes/security/openssl_advisory34.asc.sig&gt;

ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory34.asc.sig

B. 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