Summary

UPDATED Mar 17 (Corrected the affected upper fileset levels for AIX 7.1 TL5 to show that SP11 is affected. Added iFix for 7.1 TL5 SP11) There is a vulnerability in the libc.a library that affects AIX.

Vulnerability Details

CVEID:CVE-2021-29860
**DESCRIPTION:**IBM AIX could allow a non-privileged local user to exploit a vulnerability in the libc.a library to expose sensitive information.
CVSS Base score: 6.2
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/206084 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

Affected Products and Versions

Affected Product(s)	Version(s)
AIX	7.1
AIX	7.2
VIOS	3.1

The vulnerabilities in the following filesets are being addressed:

Fileset	Lower Level	Upper Level
bos.rte.libc	7.1.5.0	7.1.5.39
bos.rte.libc	7.2.3.0	7.2.3.20
bos.rte.libc	7.2.4.0	7.2.4.3
bos.rte.libc	7.2.5.0	7.2.5.100

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.libc

Remediation/Fixes

A. APARS

IBM has assigned the following APARs to this problem:

AIX Level	APAR	SP
7.1.5	IJ35673	SP12
7.2.4	IJ35675	SP05
7.2.5	IJ32736	SP03-2135

VIOS Level	APAR	SP
3.1.0	IJ35674	N/A
3.1.1	IJ35675	3.1.1.50
3.1.2	IJ32714	3.1.2.30

Subscribe to the APARs here:

<https://www.ibm.com/support/pages/apar/IJ35673&gt;

<https://www.ibm.com/support/pages/apar/IJ35674&gt;

<https://www.ibm.com/support/pages/apar/IJ35675&gt;

<https://www.ibm.com/support/pages/apar/IJ32714&gt;

<https://www.ibm.com/support/pages/apar/IJ32736&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

AIX and VIOS fixes are available.

An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 to avoid a reboot.

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

ftp://aix.software.ibm.com/aix/efixes/security/libc_fix2.tar

<http://aix.software.ibm.com/aix/efixes/security/libc_fix2.tar&gt;

<https://aix.software.ibm.com/aix/efixes/security/libc_fix2.tar&gt;

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
7.1.5.7	IJ33560m7b.211112.epkg.Z
7.1.5.8	IJ33560m8b.211112.epkg.Z
7.1.5.9	IJ35673s9a.211115.epkg.Z
7.1.5.10	IJ35673sAa.221206.epkg.Z
7.1.5.11	IJ35673sBa.230314.epkg.Z
7.2.4.2	IJ34512m2a.211112.epkg.Z
7.2.4.3	IJ34512m3a.211112.epkg.Z
7.2.4.4	IJ34512m4a.211112.epkg.Z
7.2.5.1	IJ34081m1a.211112.epkg.Z
7.2.5.2	IJ34081m2b.211112.epkg.Z

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
3.1.0.40	IJ35681m5a.211112.epkg.Z
3.1.0.50	IJ35681m6a.211112.epkg.Z
3.1.0.60	IJ35681m7a.211112.epkg.Z
3.1.1.21	IJ34512m2a.211112.epkg.Z
3.1.1.25	IJ34512m2a.211112.epkg.Z
3.1.1.30	IJ34512m3a.211112.epkg.Z
3.1.1.40	IJ34512m4a.211112.epkg.Z
3.1.2.10	IJ34081m1a.211112.epkg.Z
3.1.2.21	IJ34081m2b.211112.epkg.Z

For AIX 7.1, the provided fixes include and replace the following previously published vulnerabiilty fixes:

<https://aix.software.ibm.com/aix/efixes/security/kernel_advisory2.asc&gt;

<https://www.ibm.com/support/pages/node/6483875&gt;

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

<https://www.ibm.com/support/pages/node/6464369&gt;

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

<https://www.ibm.com/support/pages/node/6406022&gt;

<https://aix.software.ibm.com/aix/efixes/security/power9_advisory.asc&gt;

<https://www.ibm.com/support/pages/node/6370729&gt;

For AIX 7.2 and VIOS, the provided fixes should not conflict and can be installed in addition to any previously published vulnerability fixes.

To extract the fixes from the tar file:

tar xvf libc_fix2.tar

cd libc_fix2

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
a997f0597986a2c77789aac9fb256a3e0d513311ef7bd7c7dbdd67ca1ba56ae7	IJ33560m7b.211112.epkg.Z
7490cde41556847c89f96b6f079e2287e29ea4e5100db2fd96fe32f0128c24f7	IJ33560m8b.211112.epkg.Z
eb592775a18c77a0751678905ac881401aad886471b1c627abceda3bbdec5536	IJ34081m1a.211112.epkg.Z
b8f192c3a39508d11142b99ddd881fa73d929d90a8965a952356945d4b1ba31a	IJ34081m2b.211112.epkg.Z
b59b364cc0238ecd58a9b2d0b7dd853e58f29fca217a629569c10fe113dc3547	IJ34512m2a.211112.epkg.Z
d86f61f1f4d560c16681e98fd07def998e9189a55e59cb2449b5cb38b2d9a66e	IJ34512m3a.211112.epkg.Z
4839f55dd72f1a88417e899570104c48154501f2f0d22d03bf2655f29400c8ad	IJ34512m4a.211112.epkg.Z
b7de872284deb63d440146d39bd9bb77afb6b61f38d63d99c8ee08f5333685c8	IJ35673s9a.211115.epkg.Z
31bb35d16b5b0600f54648f1938e690751bf190bd80b9ef8745ebfb44e97f925	IJ35673sAa.221206.epkg.Z
78fa436ea8df1c6271eef3d2c3bca34f7385b2422115540e583e3007cc1107be	IJ35673sBa.230314.epkg.Z
846d36d37de4c925a9090de3720eacd53001b3526411e14cdc972b32d43b9b3f	IJ35681m5a.211112.epkg.Z
240a051b6fb954a3db28a5269324ad745f9ea86615724aba76615b5ae2112108	IJ35681m6a.211112.epkg.Z
b820d632ea6f601f2c748342f9c3f6719b3839aa916b531f3f0a3ea5be424f24	IJ35681m7a.211112.epkg.Z

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/&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/libc_advisory2.asc.sig&gt;

<https://aix.software.ibm.com/aix/efixes/security/libc_advisory2.asc.sig&gt;

ftp://aix.software.ibm.com/aix/efixes/security/libc_advisory2.asc.sig

C. FIX AND INTERIM FIX INSTALLATION

An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 to avoid a reboot.

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&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